performance and results annual report 2006...6 fraunhofer ilt annual report 2006 dqs certified by...

ILT

Performance and ResultsAnnual Report 2006

Annual ReportFraunhofer Institute for Laser Technology ILT2006

»Germany - Land of Ideas« is the titleof an initiative under the patronage of German president Horst Köhler,launched in 2006, the year in whichthe country was hosting the FIFA WorldCup, as a means of illustrating to theworld how innovative and creative Ger-many can be. The Fraunhofer Institutefor Laser Technology was among the365 »landmarks« selected to representthe Land of Ideas. This was not the firstsocial marketing campaign launched inan effort to make the German peoplemore aware of their strengths andencourage them to take up the chal-lenge of designing their own future.An earlier campaign in 2005, pro-claiming »You are Germany«, carried a similar message. The all-importantquestion we must ask ourselves, how-ever, is how best to channel all thatcreative energy into preserving andimproving our standard of living, giventhat the world around us is developingat such a tremendous pace.

One of the key aspects with regard to the global market is no doubt thecompetitive status of our manufactur-ing industry and the service sector thatrelies on its vitality. Because ours is ahigh-wage country, we have to con-centrate our strengths on producingpremium-quality goods, with a specialfocus on those products that can bemanufactured using a high level of au-tomation. The key to this is innovation.For it is only by designing innovativeproducts and employing automated

manufacturing techniques that we willbe able to hold onto or even expandour top-league position as an exportnation and justify our claim to beingthe Land of Ideas. It is the only way togenerate growth and create jobs forthe future. And this implies that govern-ment and industry must demonstratean even greater commitment than inthe past, both ideologically and finan-cially, to research and education.

The German government has followedthis call to action by making availablearound 15 billion euros between nowand 2009 under its high-tech strategyto promote innovation. More specifi-cally, 310 million euros have been setaside for projects in the field of opticaltechnologies, and 250 million euros forproduction technologies. Such supportgives us the motivation to continueworking on promising innovations withour partners. In the field of nano-pho-tonics, EUV technology is one of themajor thematic areas that the Fraun-hofer ILT has been driving forward formany years. Over the next few months,our industrial partner will be testingthe first alpha version of the tools wehave designed for an industrial EUVlithography plant for semiconductormanufacturing, with a view to theirfuture implementation in a full-scaleproduction environment. Interestingthings are also happening in the fieldof laser beam sources. Fiber technology,tunable lasers, high-quality fiber-coupleddiode lasers, are all areas of research in which the Fraunhofer ILT is heavilyinvolved.

Now that the European Commission’s7th Framework Programme is underway, the conditions are right for pur-suing urgently needed pre-competitiveresearch on a transnational scale in thecontext of collaborative projects. Thetechnology platform »Photonics 21«serves as a communication network forinterested companies and institutes.

The Fraunhofer ILT has actively accom-panied its implementation from thevery start. The initiative has alreadyproduced its first results: the signing-upof over 500 members, the submissionof a European agenda to EU commis-sioner Viviane Reding, and the creationof a new unit dedicated to optical tech-nologies by the European Commission.Total funding of 90 million euros hasbeen earmarked for photonics projectsin 2007 and 2008 under the 7th Frame-work Programme.

The Fraunhofer ILT intends to strengthenits focus on nanophotonics, microen-gineering and surface engineering inthe coming years. The Institute has ob-tained certification for a number ofapplications used in the aircraft industryfor the repair of engine components.There is still considerable potential fornew polishing, structuring, and gene-ration techniques. Advances in laser-assisted microfabrication processes arebeing driven by innovative sectors ofindustry including medical devices,mechatronics, and solar technology. A foretaste of things to come was pro-vided by the Aachen Colloquium forLaser Technology AKL’06 held on May3 to 5, 2006. Over 430 participantsgathered to hear about the latestdevelopments in laser technology forthe production environment and dis-cuss its future prospects. The responsewas so positive that we will be invitingthe laser community to meet in Aachenonce again in 2008, on May 7 to 9.We can promise you a highly interest-ing program and a chance to do someefficient business networking. All thatremains is for me to wish you everysuccess with your development projects.

Sincerely,

Professor Reinhart Poprawe M.A.

Fraunhofer ILT Annual Report 2006 3

Foreword

Profile of the Institute 6

Declaration of Principles 7

Business Areas 8

Board and Committees 10

Contacts 11

Core Areas 12

Services 14

Facts and Figures 16

References 19

Fraunhofer USA Center for Laser Technology CLT 20

Coopération Laser Franco-Allemande CLFA 22

Fraunhofer Alliance Surface Engineering and Photonics VOP 24

The Fraunhofer-Gesellschaft at a Glance 26

Laser Technology at RWTH Aachen 28

Cluster of Excellence »Integrative Production Technology for High-Wage Countries« 30

PhotonAix e. V. - Competence Network for Optical Technologies 32

Some Special Research Results from the Business Areas of Fraunhofer ILT

Laser and Plasma Sources 33 - 58

Laser Material Processing 59 - 100

Laser Plant and System Technology 101 - 110

Laser Measurement and Testing Technology 111 - 132

European Laser Institute ELI 110

Patents 133

Dissertations 134

Diploma Theses 134

Scientific Publications 135

Lectures 137

Conventions and Conferences 141

Trade Fairs 145

Publications 146

Technical Book »Laser Technology for Manufacturing« 149

Video Films and Multimedia Software 150

Information Service 152

Imprint 153


Contents

6 Fraunhofer ILT Annual Report 2006

DQS certified by DIN EN ISO 9001Reg.-No.: DE-69572-01

Short Profile

ILT - for more than twenty years, this ab-breviation has stood for extensive know-how in laser technology. Innovative solutions for manufacturing and pro-duction problems, development ofnew technical components, competentadvice and training, highly-qualifiedpersonnel, the latest technologies andan international reputation: these arethe guarantors for long-term businessrelations. The numerous customers ofthe Fraunhofer Institute for Laser Tech-nology ILT belong to various sectorslike automobile industry, mechanicalengineering, chemical and electricalengineering, steel construction, preci-sion mechanics and optics.

With more than 250 employees and10.000 m2 of usable floor space theFraunhofer Institute for Laser Technolo-gy is world-wide one of the most important development and contractresearch institutes of its specific field.The four business areas cover a widerange of actual and vertical integratedtopics. In the business area »laser andplasma sources« development activitiesare concentrated on innovative diodeand solid state lasers for industrial useas well as compact EUV-sources for lithographic use in semiconductorproduction. The business area »lasermaterial processing« offers solutions in cutting, ablation, drilling, welding,soldering, surface treatment and microprocessing. The activities cover a widerange of applications from macro processing via nano structuring to biophotonics.

In the business area »laser plant andsystem technology« prototypes are developed, built up and installed on site.Process monitoring and control as wellas system components and controlsoftware are part of the activities. Inthe business area »laser measurementand testing technology« processes andsystems for inspection of surfaces, forchemical analysis, for testing the accu-racy of dimensions and geometry ofworkpieces as well as for analysis ofstatic and dynamic deformations aredeveloped.

The comprehensive offer of services of the Fraunhofer Institute for Laser Technology ranges from research anddevelopment as well as system construc-tion and quality assurance to adviceand training. Industrial laser systemsfrom various manufacturers as well asan extensive infrastructure are availablefor the work on research and development projects.

In the Laser User Center of the Fraun-hofer Institute for Laser Technologyguest companies work in their own separated laboratories and offices. Thebasis of this special form of technologytransfer is a long-term cooperation agreement with the institute in thefield of research and development. The surplus value lies in the use of thetechnical infrastructure and in theinformation exchange with ILT´sexperts. Already 10 companies profitfrom the advantages of the Laser UserCenter. Besides laser manufacturersand laser users, entrepreneurs from the areas of special machine production,laser processing and laser measurementfind a suitable frame to realize their ideason an industrial scale.

Profile of the Institute

Mission

We occupy an international top positionin transferring laser technology toindustrial application.

We continually expand the knowledgebase and know-how in our sector andmake significant contributions to theongoing development of science andtechnology.

Working with our partners in industry,science and government, we createinnovations on the basis of new beamsources and new applications.

Customers

The customers needs are the focus ofour work.

Discretion, fairness and a spirit of part-nership are top priorities in our customerrelationships. Our customers can relyon us.

We tailor solutions and their cost-effective implementation to thedemands and expectations of ourcustomers, with the objective of creating a competitive advantage.

We support industry’s needs for newspecialists and managerial staffthrough project-based partnershipswith our customers.

We want our customers to be satisfied- because we want them to return.

Chances

We strategically expand our knowledgebase across the network.

Fascination: Laser

The unique characteristics of laser lightand the resulting diversity of applica-tions, are a constant source of inspirationand fascination.

Staff

Teamwork between the individual and the group is the foundation of oursuccess.

Strengths

Our broad spectrum of resources enables us to offer one-stop solutions.

Management style

Cooperative, demanding and suppor-tive. Knowing the value of our staff asindividuals and the value of theirknow-how and their commitmentforms the basis of our managementphilosophy. We involve our staff in theformulation of goals and the decision-making process. We place a high valueon effective communication, goal-oriented and efficient work and cleardecisions.

Position

We work within vertical structures,from research to application.

Our expertise extends from beam source,machining and measuring techniques,to application, through to integrationof systems into the customer’s produc-tion line.


Declaration of Principles


Business Areas

Laser and Plasma Sources

This business area encompasses thedevelopment of diode laser modulesand systems as well as diode-pumpedsolid-state lasers with different reso-nator structures (stab,slab,fiber), the design of new diode laser structures,the microassembly of diode lasers and optical components, and the develop-ment of plasma systems.

For more than 10 years spinn-offs ofthe Fraunhofer ILT are set up in the framework of some projects. In coope-ration with the Fraunhofer IAF newstructures are being designed whichpermit the manufacture of diode lasersdemonstrating higher beam quality. The business area continues to enjoy a unique reputation in the assembly of high-power diode lasers and in particular the installation of automatedassembly and test facilities. Work inthe plasma technology sphere focuseson the development of EUV beamsources for semiconductor lithography.The main target markets for the busi-ness area as a whole are laser machining,medical engineering and metrology,along with the component market forinformation and communications tech-nology.

Laser Material Processing

Production processes addressed by this business area include cutting andjoining techniques applying micro- andmacro-technology, as well as surfaceengineering. The services providedextend from process development forthe manufacture of sector-specific products and the integration of theseprocesses in production lines, throughsimulation services for laser applications,to the production of samples in sup-port of series production start-up. Thestrength of the business area is rootedin its extensive process know-how,which is tailored to specific customerrequirements in each case. In additionto process development, the businessarea offers complete system solutionswhich utilize selected technology net-works. Customers are offered laser-specific solutions that encompass designengineering, material specification,product design, production equipmentand quality assurance. In addition tothe target market of material process-ing, the business area also addressescustomers in the medical engineering,biotechnology and chemical sectors.


Business Areas

Laser Plant and System Technology

This business area focuses on the deve-lopment of prototype equipment forlaser and plasma-technology applica-tions, as well as on laser systemsengineering, particularly in the fields of automation and quality assurance.Areas of application embrace welding,cutting, hardening, repair coating, drilling and micro-joining. The systemtechnology offered provides completesolutions for process monitoring, com-ponents and control systems for preci-sion machining, laser-specific CAD/CAMtechnology modules, as well as soft-ware for measurement, open- and closed-loop control and testing. For its work in process monitoring in parti-cular the business area can draw onextensive and, where required, patent-protected know-how. In this sectornumerous systems have already beenlicensed for companies. Target marketsinclude laser equipment and compo-nent manufacture as well as all sectorsof production industry which deploylasers in their manufacturing activity or intend to do so.

Laser Measurement and Testing Technology

The services provided by this businessarea include the development of mea-surement and testing processes and related equipment for material analysisand for geometric testing and surfaceinspection. The requisite measurementand testing software is tailored to customer-specific problem areas. Materialanalysis is based on the deployment oflaser-spectroscopic processes, focusingon the analysis of metallic and oxidicmaterials, identification testing of high-alloy steels, rapid recognition of mate-rials for recycling tasks and analysis ofgases and dust. Special electronic com-ponents are developed for the parallelprocessing of detector signals of highbandwidth.

In biophotonics joint projects are car-ried out in the field of highly sensitivefluorecence detection for protein chipsand laser scattered light measurementsin sub-µl test volumes for protein crystallization. As part of the area’s work on geometric testing and surface inspection components, devices andequipment are being developed for obtaining 1 to 3D information aboutthe geometry or surface properties ofworkpieces. These include processesand special systems for testing the stability of bar and strip products anddevices for the 1D to 3D scanning ofunit goods. Target markets include theproduction and the recycling industrywhich conduct measurement andtesting fast and close to the process.

Board

The Board of Trustees advises theFraunhofer-Gesellschaft as well as theInstitute’s management and supportsthe links between interest groups andthe research activities at the institute.The Board of Trustees during the yearunder review consisted of:

C. Baasel (Vorsitzender)Carl Baasel Lasertechnik GmbH

Dr. R. G. Gossink Philips Forschungslabor GmbH

H.-J. HaeppDaimlerChrysler AG

Dr. Ulrich HefterRofin-Sinar Laser GmbH

Dipl.-Ing. H. Hornig BMW AG

Dr. U. Jaroni ThyssenKrupp Stahl AG

Prof. Dr. G. Marowsky Laserlaboratorium Göttingen e. V.

MinRat Dipl.-Phys. T. Monsau Ministerium für Arbeit und Soziales,Qualifikation und Technologie des Landes NRW

Dr. Rüdiger MüllerOsram Opto Semiconductors GmbH & Co. OHG

Dr. Joseph PankertPhilips Lighting B.V.

Prof. R. Salathé Ecole Polytechnique Fédéral de Lausanne

MinR Dr. Frank Schlie-RoosenBundesministerium für Bildungund Forschung BMBF

Dr. Ulrich StegerMinisterium für Innovation, Wissenschaft, Forschungund Technologie des Landes NRW

Dr. Dieter SteegmüllerDaimlerChrysler AG

Dr. Klaus WallmerothTRUMPF Laser GmbH & Co. KG

The 22nd Board of Trustees meetingwas held on September 20, 2006 at the Fraunhofer ILT in Aachen.

Directors’ Committee

The Directors’ Committee advises theInstitute’s managers and is involved in deciding on research and businesspolicy. The members of this committeeare: Vasvija Alagic, Dipl.-Phys. A. Bauer, Dr. K. Boucke, Dr. A. Gillner,Dr. J. Gottmann, Dipl.-Ing. H. D. Hoff-mann, Dr. S. Kaierle, Dr. I. Kelbassa (since Aug. 2006), Dr. E.-W. Kreutz,Prof. Dr. P. Loosen, Dr. W. Neff, Dr. R.Noll, Dr. D. Petring, Prof. Dr. R. Poprawe,Prof. Dr. W. Schulz, B. Theisen,Dr. B. Weikl, Dr. K. Wissenbach.

Health & Safety Committee

The Health & Safety Committee is responsible for all aspects of safety and laser safety at the Fraunhofer ILT.Members of this committee are: Vasvija Alagic, K. Bongard, M. Brankers,A. Hilgers, Dr. E.-W. Kreutz, A. Lennertz,Dr. W. Neff, E. Neuroth, Dipl.-Ing M. Poggel, Prof. Dr. R. Poprawe, B. Theisen, Dipl.-Ing. F. Voigt, Dipl.-Ing.N. Wolf, Dr. R. Keul (Berufsgenossen-schaftlicher Arbeitsmedizinischer DienstBAD).

Science & Technology Council

The Fraunhofer-Gesellschaft’s Science & Technology Council supports and advises the various bodies of theFraunhofer-Gesellschaft on scientificand technical issues. The members are the institutes’directors and onerepresentative elected from the science/technology staff per institute.

Members of the Council from the ILTare: Prof. Dr. R. Poprawe, B. Theisen,Dr. C. Janzen.

Department of Laser Technology LLTat the RWTH Aachen

The Fraunhofer ILT is home to most ofthe Department of Laser Technology.This means that a close scientific relation-ship between the Fraunhofer ILT andthe Department of Laser Technologyhas been built up, based on a contractof cooperation. Prof. Dr. rer. nat. Reinhart Poprawe M.A. is Director ofthe Department of Laser Technology, Dr. Ingomar Kelbassa is Academic Director z. A..

Betriebsrat

In March 2003 the staff associationwas elected by the employees of theFraunhofer ILT and the Department of Laser Technology. Members are:Dipl.-Ing. P. Abels, Dipl.-Ing. G. Backes,M. Brankers, Dipl.-Phys. J. Geiger, M. Janßen, Dipl.-Phys. G. Otto, B. Theisen (chair), Dr. A. Weisheit,Dipl.-Ing. N. Wolf.


Board and Committees

Prof. Dr. Reinhart Poprawe (-110)Director

Dipl.-Phys. Axel Bauer (-194)Marketing and Communication

Vasvija Alagic (-181)Administration

Dr. Bruno Weikl (-134)IT-Management

Dr. Alexander Drenker (-223)Quality Management

Prof. Dr. Peter Loosen (-162)Vice Director

Dr. Konstantin Boucke (-132)Laser Components

Dipl.-Ing. Dieter Hoffmann (-206)Solid State and Diode Lasers

Dr. Reinhard Noll (-138)Laser Measurement and Testing Technology

Dr. Willi Neff (-142)Plasma Technology

Dr. Dirk Petring (-210)Cutting and Joining

Dr. Konrad Wissenbach (-147)Surface Treatment

Dr. Arnold Gillner (-148)Micro Technology

Dr. Stefan Kaierle (-212)System Technology

Prof. Dr. W. Schulz (-204)Modelling and Simulation


Contacts


Core Areas

Laser ComponentsDr. Konstantin Boucke

• Active und passive cooling of diode lasers

• Expansion-matched coolers and mounting technologies for laser diode bars

• Mounting of laser diode bars with indium- and AuSn solder

• Characterization and testing of diode lasers in the wavelength regime between 630 nm and 2.1 µm

• Design and assembly of micro-optical systems

• Fiber coupling for singlemode and multimode fibers

• Automation of high-precision assembly processes for lasers and optical systems

Solid State and Diode LasersDipl.-Ing. Dieter Hoffmann

• Development of solid state and diode lasers

• Development of fiber lasers • Methods and components

for frequency doubling • Optical design for lasers, beam guid-

ing and forming of laser radiation • Development of diode laser modules

and systems • Design and characterization

of optical components • Development of components

for solid state and diode lasers

Laser Measurement and TestingTechnologyDr. Reinhard Noll

• Laser measurement processes for online inspection tasks

• Development, construction, integration and testing of laser measurement and testing equipment

• Chemical analysis of solid, liquid and gaseous substances with laser spectroscopy

• Spectroscopic monitoring of welding processes

• Fluorescence analysis • Quantification of protein

interactions using label-free laser scattering methods

• In vivo diagnostics for online mo-nitoring of minimal invasive surgery

• Measurement of distances, profiles and shapes with laser triangulation

• Real time operation and automation

Plasma TechnologyDr. Willi Neff

• Development of plasma based EUV/XUV-sources

• Development, construction and integration of components for EUV/XUV-measuring systems (microscopy, surface characterization,measurement of reflectivity …)

• Power generators for pulsed plasma formation

• Process control and monitoring systems for spatially arranged systems based on micro seconds

• Atmospheric pressure plasma for surface modification (sterilization of packaging material, functiona-lization …)

Cutting and JoiningDr. Dirk Petring

• Cutting, perforating, drilling, deep-engraving

• Welding, brazing, soldering• High-speed processing• Thick section processing• Cutting and joining of special

materials• Welding with filler material• Laser-arc hybrid technologies• Product-oriented process

optimization• Multi-functional manufacturing

processes• Design and implementation

of processing heads• Sensor-based process control• Computer-supported simulation

and optimization• Multimedia training and information

systems

Surface Treatment Dr. Konrad Wissenbach

• Transformation hardening, remelting,cladding, alloying and dispersing for the production of load orientatedlayers

• Development of powder feeding systems

• Heat treatment of coated and uncoated surfaces

• Functionalising of nano-particulate coatings

• Cleaning and modification of surfacessuch as burr removing, activation andstructuring

• Rapid prototyping und rapid manufacturing for production of metallic parts and tools

• Polishing of metals and glass


Core Areas

Micro TechnologyDr. Arnold Gillner

• Laser micro soldering and micro welding

• Laser supported adjustment • Laser assisted deep drawing

and punching • Micro tool technology • Precision cutting and drilling

of metals, ceramics, semiconductorsand diamonds

• Micro structuring with excimer, Nd:YAG- and short pulse lasers

• Marking and lettering• Cutting and perforating of paper,

plastics and composite materials • Welding of thermoplasts and

thermoplastic elastomeres • Laser medicine • Biophotonics • Photochemical processes • Nano structuring with laser

radiation • Laser modification for bio

functional surfaces • Micro manipulation of cells

with laser radiation

Modelling and SimulationProf. Dr. W. Schulz

• Generation of EUV-radiation • Design of optical resonators

for high power diode lasers • Beam guiding, beam shaping • Flow and heat transport in gases

and melt • Movement of phase boundaries • Dynamical models of removing,

cutting, welding and drilling • Evaluation and visualization of data

from measurement and simulation • Computational steering of

simulations• Numerical methods and codes,

finite elements and finite volumes in domains with free boundaries, adaptive cross linking

• Diagnostics of laser radiation and laser manufacturing processes

System TechnologyDr. Stefan Kaierle

• Process monitoring and control for quality assurance

• Process analysis and process development tools

• Development of online sensors and control systems (e. g. seam tracking,velocity measurement, positioning, distance measurement and control, multi-sensor technology and net-works)

• Automated testing of processing results (e. g. systems for seam evaluation)

• Process trials and testing • Feasibility studies • Pilot-run series• Integration of laser technology into

existing production facilities • Remote and scanner applications • Integrated processing heads • CAD/CAM-supported laser

processing • Offline path planning and simulation• Conception and design of plants • Pilot plants • Control techniques for laser plants • Consulting, education and training


Services

The services of the Fraunhofer Institutefor Laser Technology ILT are continuallybeing adapted to the practical require-ments of industry and include the solution of manufacturing problems as well as the realization of test series. In detail this means: • development of laser beam sources • manufacturing and assembling

technology • pulsed power supplies and control

technology • beam guiding and forming • development, set-up and testing

of pilot plants • process development • process monitoring and control • model and test series• integration of laser technology into

already existing production plants • X-ray and plasma systems

Cooperations with R&D-Partners

The Fraunhofer Institute for Laser Technology ILT is cooperating withR&D-partners in different ways: • Realization of bilateral, company

specific R&D-projects with and without public support (contract for work and services)

• participation of companies in public-funded cooperative projects (cofinancing contract)

• Production of test, pilot and prototype series by Fraunhofer ILT to determine the reliability of the process and minimize the starting risk (contract for work and services)

• companies with guest status at Fraunhofer ILT (special cooperation contracts)

By means of cooperation with otherresearch organizations and specializedcompanies the Fraunhofer Institute forLaser Technology offers solutions evenin the case of interdisciplinary tasks. A special advantage hereby consists inthe direct access to the large resourcesof the Fraunhofer Society.

During the implementation phase of new laser processes and products, companies can acquire ‘guest status’at the Fraunhofer Institute for LaserTechnology and use the equipment,infrastructure and know-how of the institute as well as install their own systems.

Services

Facilities

The usable floor space at the Fraun-hofer Institute for Laser Technology ILTamounts to more than 10,000 m2.

Technical InfrastructureThe technical infrastructure of the institute includes a mechanical and electronic workshop, a metallurgic laboratory, a photographic laboratory,a laboratory for optical metrology aswell as a department for design andconstruction. The Fraunhofer ILT alsohas a video conference room and acomputer network.

Scientific Infrastructure The scientific infrastructure includes a library with international literature,patent and literature data bases as well as programmes for calculation of scientific problems and data bases for process documentation.

Equipment The equipment of the Fraunhofer Institute for Laser Technology ILT is permanently being adapted to the state-of-the-art. At present, essentialcomponents are: • CO2-lasers up to 20 kW• lamps and diode pumped solid

state lasers up to 8 kw• fiber lasers, up to 4 kW• diode laser systems up to 3 kW • SLAB laser• excimer lasers• ultra short pulse laser• broardband tunable laser• five-axis gantry systems• three-axis processing stations • beam guiding systems• robot systems

• sensors for process control in laser material processing

• direct-writing and laser-PVD stations• clean rooms for assembly of diode

lasers, diode laser systems and diode pumped solid state lasers

• live sience laboratory with S1 and S2 classification

• devices for process diagnostics and high speed video analysis

• laser spectroscopic systems for the chemical analysis of solid, liquid andgaseous materials

• laser triangulation sensors for distance and contour measurement

• laser coordinate measuring machine • confocal laser scanning microscopy

Fraunhofer ILT abroad

Since its foundation, Fraunhofer ILT has been involved in many internationalcooperations. The objective of thesecooperations is to recognize newtrends and current developments andto acquire further know-how. The customers of Fraunhofer ILT can directlybenefit from this. Fraunhofer ILT carriesout bilateral projects as well as interna-tional cooperative projects with foreigncompanies and subsidiaries of Germancompanies abroad. These companiescan also contact Fraunhofer ILTthrough: • international subsidiaries of

Fraunhofer ILT • foreign cooperation partners of

Fraunhofer ILT• liaison offices of the Fraunhofer

Society abroad


© AVIA-Luftbild, AachenDipl.-Ing. Martin Jochum

Services

Employees 2006

Employees

• 6 Mitarbeiter haben ihre Promotionabgeschlossen

• 26 Studenten haben ihre Diplomarbeit am Fraunhofer ILTdurchgeführt

45 % Undergraduate assistants

8 % Administrative staff

12% Technical staff

3 % External employees, trainees

32 % Scientists/engineers

Facts and Figures


Employees at the Fraunhofer ILT 2006 number

Personnel 137- Scientists and engineers 84- Technical staff 33- Administrative staff 20Other employees 128- Undergraduate assistants 119- External employees 7- Trainees 2Total number of employees at the Fraunhofer ILT 265

• 6 members of staff completedtheir doctorates

• 26 undergraduates carried out their final year projects at the Fraunhofer ILT

Revenues and Expenses

Expenses 2006 (100 %) Revenues 2006 (100 %)


Facts and Figures

43,5 % Material costs

13 % Investments

43,5 % Staff costs

34 % Additional financing from Federal Government, States and EU

27 % Industrial revenues

39 % Basic financing from the Fraunhofer-Gesellschaft

Expenses 2006 Mill. EUR

- Staff costs 9,0- Material costs 9,0Expenses operating budget 18,0

Investments 2,7

Revenues 2006 Mill. EUR

- Industrial revenues 7,0- Additional financing from Federal Government,

States and the EU 6,1- Basic financing from the Fraunhofer-Gesellschaft 4,9Revenues operating budget 18,0- Revenues from projects abroad (already included in total) 3,3

Investment revenues from industry 0,3

Fraunhofer industry ρInd 41 %

Budget Growth

The following graph illustrates thebudget trend over the last 7 years.

Facts and Figures


14,8

17,5 17,116,4

17,4

18,618,0

Project revenues - public funding

Project revenues - industrial funding

Basic financing by Fraunhofer

References

March 2007Printed with the kind permission of our partners.

The companies listed here represent a selection of the Fraunhofer ILT’smany clients.

Short Profile

The Fraunhofer Center for Laser Tech-nology CLT, located in Plymouth,Michigan, has a 1250 m2 developmentcenter housing $9 million worth of themost varied, leading edge laser equip-ment in North America. This area hasestablished itself as the center for laserproduction, system integration andindustrial users in the USA.

The on-going goals are:• Integration in scientific and

industrial development in the USA• Growth in know-how by faster

recognition of trends in the field of laser and production technology

• Accelerated use of R&D and work methods, in which the USA is the leader

• Know-how growth through close cooperation with the Wayne State University and the University of Michigan.

• Strengthening position in the R&D market

• Increase of industrial return from the USA

• Increase of motivation and qualification level of employees

The central philosophy of FraunhoferUSA is the creation of a German-American joint venture where give and take occur in harmony. The win-winsituation is an essential prerequisite for both sides. The Fraunhofer Gesellschaft is always interested inconsidering and trying to develop relationships on the American side that strengthen mutually.

The American partners’ interest concentrates on: • Using the competence of the

Fraunhofer Institutes for American companies

• Using the experience in the introduction of new technologies

• Providing the connection between industry and university

• Providing practical training for students and graduate students

In cooperation with the University ofMichigan fiber lasers are developed.Basic technology and new concepts forcomponents and fibers emerge at theuniversity. Fraunhofer undertakes thedevelopment of suitable pump sour-ces, system integration and prototypebuilding. The focus of the investigationis on diffraction limited radiation, fle-xible pulse characteristic and monolithicconstruction, as well as systems withkW-output power are deployed inten-sively.

In collaboration with the Wayne StateUniversity, durably stable implants forneurostimulation of the human brainare being developed. The CLT is alsothe main sponsor of the »Laserspot«organization, founded in 2000, andmeanwhile supported by over 20members. The purpose of Laserspot isto promote applications of laser tech-nology in various branches of industry.

Due to rapid commercialization ofresearch results and common process-ing of research results, Visotek wasestablished out of the CLT in 2001.Visotek produces intelligent laser toolsand runs job order production for theautomobile industry. Fiber coupleddiode lasers with kilowatt outputpower were successfully transferredfrom the research into the market. A further common development is aspecial optic, which enables rapid twodimensional scanning and auto focusfor lasers with an output power up to


Fraunhofer USA Center for Laser Technology CLT

15 kW. This optic was successfullyapplied in the shipbuilding for weldingof thick plates with variable weld seamwidth and in the automotive industryfor robotic remote welding. Visotekcan perform 250 welding spots perminute with 6 kW laser power.

Services

The CLT offers services in the field of laser processing, the developmentof optical components and speciallaser systems. This covers the entirespectrum from feasibility studies, process development to pre-seriesdevelopment as well as prototype production of laser beam sources andlaser systems which are ready to use.As an independent institution smalland mid-sized companies are given theopportunity to develop and test theirprocesses on Fraunhofer machineswith the help of Fraunhofer personnel.It is also possible to develop and testcomplete systems at the CLT. Ourcustomers come from the automobileindustry, construction industry, shipbuilding and medical engineering.

Employees

Both Germans and Americans areemployed at the CLT. The goal is torotate German employees so that thecollected experience can be broughtover to the parent institutes and tooffer German employees the opportu-nity to become further qualified duringtheir stay in the USA. Furthermore, students from the Technical Universityin Aachen write their diploma thesis in the USA.

Equipment

Current equipment in the CLT lab con-sists of: CO2 lasers with up to 8 kWpower, Nd:YAG laser from 250 W to4.4 kW, diode lasers from 30 W to 3 kW, frequency trebled Nd:YAG laserand excimer laser, a number of specialand hybrid optics, a series of 3, 5 and6 axes systems, as well as severalrobots.

References

• US Air Force Research Laboratories• Office of Naval Research• Michigan Lifescience Corridor• Alcan• Borg Warner Automotive• Dana Corporation• DaimlerChrysler• Ford Motor Company• General Motors• Hemlock Semiconductors• Nuvonyx• LASAG• PRC• Rofin Sinar• Spectra Physics• Siemens VDO• Trumpf• Visteon

Operating Budget 2006*

*Post-calculation has not occurred yet

Contact

Dr. Stefan HeinemannDirector

46025 Port StreetPlymouthMichigan 48170USA

Telefon: +1 734 / 354 -6300Extension: -210Fax: +1 734 / 354 -3335

[email protected]

Mio. US$

Operating budget 2.35 - Staff costs 1.15- Material costs 1.20


Fraunhofer USA Center for Laser Technology CLT

Short Profile

At the CLFA in Paris, the FraunhoferInstitute for Laser Technology ILT hasbeen cooperating since 1997 with leading French research organizations,including ARMINES, the École NationaleSupérieure des Mines de Paris ENSMP,the Institut de Soudure, the InstitutUniversitaire de Technologie du Creusot,the École Nationale Supérieure deMécanique et des MicrotechniquesENSMM in Besançon and other majorlaser application centers in France.Multidisciplinary teams of specialistsfrom Germany and France work to-gether on the transfer of laserassistedmanufacturing processes to Europeanindustry. The Coopération Laser Franco-Allemande is a member of the ClubLaser et Procédés, the French associationof laser manufacturers and users.

The on-going goals of the CLFA are: • Integration into scientific and

industrial development in France• Growth in know-how by faster

recognition of trends in the fields of European laser and production technology

• Strengthening the position in the R&D market

• Assembly of a European competencecenter for laser technology

• Increase of mobility and qualificationlevel of employees

The CLFA is actively participating in therealization of European research and isa result of increasing link of applicationoriented research and development inthe field of laser technology in Europe.The cooperation of the Fraunhofer ILTwith the French partners contributes to the improvement of the presence ofthe Fraunhofer Gesellschaft in Europewith the advantages for the Frenchand German sides equally taken intoconsideration. On an international scalethis cooperation further strengthens theleading position of European industryin the laser supported manufacturingprocess.

The French partners’ interests concen-trate on:• Using the competence of the

Fraunhofer ILT for French companies• Using the experience of the Fraun-

hofer ILT in the introduction of new technologies

• Providing the connection between industry and university with practicaltraining for students and graduate students


Coopération Laser Franco-Allemande CLFA

Visit of the French researchminister François Goulard atthe »Fête de la Science« fromOctober 9 bis 15, 2006 in Paris.

Services

The CLFA offers services in the field oflaser material processing. This coversthe entire spectrum from applicationoriented fundamental research andtraining, feasibility studies and processdevelopment to pre-series developmentand system integration. Small and mid-sized companies have the opportunityhere to get to know and test lasertechnology in an independent system.The open development platform allowsthe French customers to test and qua-lify new laser supported manufacturingprocesses.

Employees

At the CLFA employees from Franceand Germany work together. A mutualexchange of personnel occurs betweenAachen and Paris for joint projects. The employees therefore have theopportunity to improve their compe-tence especially with regard to mobilityand international project management.

Equipment

In addition to the technical resourcesavailable at the Fraunhofer ILT in Germany, the CLFA possesses its own infrastructure at the Centre desMatériaux Pierre-Marie Fourt, an out-station of the Ecole des Mines de Parisbased in Evry, south of Paris. Facilitiesinclude access to the center’s materialanalysis laboratories. The technicalinfrastructure of other French partnerscan also be shared on a project- orcustomer-specific basis.

Locations

Paris - at the École Nationale Supérieuredes Mines de Paris ENSMP, in centralParis.

Evry - on the premises of the Centredes Matériaux Pierre-Marie Fourt,roughly 40 km south of Paris.

Contact

Dr. Wolfgang KnappDirector

CLFA c/o Armines60 Boulevard Saint Michel75272 PARIS Cedex 6France

Telephone: +33 1 / 4051 -9476 Fax: +33 1/4634-2305

[email protected]/clfa.html


Coopération Laser Franco-Allemande CLFA

Competence by Networking

Six Fraunhofer Institutes cooperate inthe Network Surface Engineering andPhotonics VOP. Complementary com-petencies allow to adapt the researchactivities to the rapid technologicalprogress in all industrial applicationfields in a permanent, apace and flexibleway. Co-ordinated strategies, in linewith the currents needs of the market,create synergy effects and provide a larger service for the benefit of thecustomers.

Fraunhofer Institute for ElectronBeam and Plasma Technology FEP

The ambition of FEP is the researchand development of innovative processes for the utilisation of highperformance electron beams and vacuum sealed plasmas for surfacetechnology. Priority is given to problemslike process monitoring, quality control,reproducibility, scaling, and profitability.

Fraunhofer Institute for PhysicalMeasurement Techniques IPM

The Fraunhofer IPM develops opticalsystems for applications in spectros-copy and light exposure technology. A major focus is the realisation of highlydynamical systems. Besides a rapidactivation, they require special compe-tencies in signal processing as realisedthrough robust and lowmaintenancemeasurement systems for the infra-structure monitoring of highspeed roads.

Fraunhofer Institute forLaser Technology ILT

In the area of laser technology, theinteractive relationship between laserdevelopment and laser applications isof prime importance. New lasers allownew applications, and new applicationsset the stage for new laser systems.This is why the Fraunhofer ILT is conti-nually expanding its core competenciesthrough close cooperation with leadinglaser manufacturers and innovativelaser consumers.

Above: Fraunhofer FEPMiddle: Fraunhofer IPMBelow: Fraunhofer ILT


Fraunhofer Alliance Surface Engineering and Photonics VOP

Fraunhofer Institute for SurfaceEngineering and Thin Films IST

As an industry oriented R&D servicecentre, the Fraunhofer Institute forSurface Engineering and Thin Films ISTis pooling competencies in the areasfilm deposition, coating applicationand film characterization. Presently, theinstitute is operating in the followingbusiness fields: mechanical and auto-motive engineering; tools; energy;glass and facade; optics; informationand communication; life science andecology.

Fraunhofer Institute for AppliedOptics and Precision Engineering IOF

The core of the research activity ofFraunhofer IOF is optical systemsengineering aimed at a steady improve-ment of light control. The institute'sfocus is on multifunctional optical coatings, optical measurement systems,micro-optical systems, systems for thecharacterisation of optics and compo-nents for precision mechanics assem-blies and systems.

Fraunhofer Institute for Materialand Beam Technology IWS

The Fraunhofer IWS is conductingresearch in the areas of laser techno-logy (e.g. laser beam welding, cutting,hardening), surface technology (e.g.build-up welding), micro machining aswell as thin film and nano technology.The integration of material testing andcharacterisation into research anddevelopment constitutes and upgradesthe IWS spectrum.

Contact und Coordination

Speaker of the NetworkProf. Dr. Eckhard Beyer

CoordinationUdo KlotzbachTelephone: ++49 (0)351 / [email protected]

The Instituteswww.fep.fraunhofer.dewww.ipm.fraunhofer.dewww.ilt.fraunhofer.dewww.ist.fraunhofer.dewww.iof.fraunhofer.dewww.iws.fraunhofer.de

Above: Fraunhofer ISTMiddle: Fraunhofer IOFBelow: Fraunhofer IWS


IST

ILT

IPM

IOF

IWS

FEP

Fraunhofer Network Surface Engineering and Photonics VOP

The Fraunhofer-Gesellschaft

Research of practical utility lies at theheart of all activities pursued by theFraunhofer-Gesellschaft. Founded in1949, the research organization under-takes applied research that drives eco-nomic development and serves thewider benefit of society. Its services aresolicited by customers and contractualpartners in industry, the service sectorand public administration. The orga-nization also accepts commissions fromGerman federal and Länder ministriesand government departments to parti-cipate in future-oriented research pro-jects with the aim of finding innovativesolutions to issues concerning the in-dustrial economy and society in general.

Applied research has a knock-on effectthat extends beyond the direct benefitsperceived by the customer: Throughtheir research and development work,the Fraunhofer Institutes help to rein-force the competitive strength of theeconomy in their local region, andthroughout Germany and Europe. Theydo so by promoting innovation, accele-rating technological progress, improvingthe acceptance of new technologies,and not least by disseminating theirknowledge and helping to train theurgently needed future generation ofscientists and engineers.

As an employer, the Fraunhofer-Gesell-schaft offers its staff the opportunity todevelop the professional and personalskills that will allow them to take uppositions of responsibility within theirinstitute, in other scientific domains, in industry and in society. Studentsworking at the Fraunhofer Instituteshave excellent prospects of starting anddeveloping a career in industry by virtueof the practical training and experiencethey have acquired.

At present, the Fraunhofer-Gesellschaftmaintains more than 80 research units,including 56 Fraunhofer Institutes, at40 different locations in Germany. Themajority of the 12,500 staff are quali-fied scientists and engineers, who workwith an annual research budget of EUR1.2 billion. Of this sum, more than EUR1 billion is generated through contractresearch. Two thirds of the Fraunhofer-Gesellschaft’s contract research revenueis derived from contracts with industryand from publicly financed researchprojects. Only one third is contributedby the German federal and Ländergovernments in the form of institutionalfunding, enabling the institutes towork ahead on solutions to problemsthat will not become acutely relevant to industry and society until five or tenyears from now.

Affiliated research centers and represen-tative offices in Europe, the USA andAsia provide contact with the regionsof greatest importance to present andfuture scientific progress and economicdevelopment.

The Fraunhofer-Gesellschaft is a re-cognized non-profit organization which takes its name from Joseph von Fraunhofer (1787-1826), the illustriousMunich researcher, inventor andentrepreneur.

Fields of Research

The Fraunhofer-Gesellschaft concentrateson research in the following fields:• Materials technology, component

behavior• Production and manufacturing

technology• Information and communication

technology• Microelectronics, microsystems

engineering• Sensor systems, testing technology

• Process engineering• Energy and construction

engineering, environmental and health research

• Technical/economic studies, information transfer

Target Groups

The Fraunhofer-Gesellschaft is commit-ted to working for the economy as awhole, for individual businesses andfor society. The targets and benefi-ciaries of our research activities are:• The Economy: Small, medium-sized

and large companies from industry and service sectors can all benefit from contract research. The Fraun-hofer-Gesellschaft develops con-crete, practical and innovative solutions and furthers the applicationof new technologies.The Fraun-hofer-Gesellschaft is an important ‘supplier’ of innovative know-how to small and medium-sized com-panies (SMEs) not equipped with their own R&D department.

• Country and society: Strategic research projects are carried out at federal and state level, promoting key technologies or innovations in fields of particular public interest, e.g. environmental protection, energy technologies and preven-tative health care. The Fraunhofer-Gesellschaft also participates in technology programs initiated by the European Union.


The Fraunhofer-Gesellschaft at a Glance

Range of Services

The Fraunhofer-Gesellschaft developsproducts and services to full maturity.We work closely with our clients tocreate individual solutions, combiningthe efforts of several Fraunhofer insti-tutes if necessary, in order to developmore complex system solutions. Theservices provided by the Fraunhofer-Gesellschaft are:• Product optimization and

development through to prototype manufacture

• Optimization and development of technologies and production processes

• Support for the introduction of new technologies via:- Testing in demonstration centers

using highly advanced equipment- In-house training for the staff

involved- On-going support, also sub-

sequent to the introduction of new processes and products

• Assistance in assessing new technologies via:- Feasibility studies- Market analyses- Trend analyses- Life cycle analyses- Evaluation of cost-effectiveness

• Supplementary services, e.g.:- Advice on funding, especially

for SMEs- Testing services and quality

validation

The Advantages of Contract Research

Cooperation between all the Fraunho-fer institutes means that our clientshave access to a large number ofexperts covering a wide range of com-petencies. Thanks to common qualitystandards and professional projectmanagement, the Fraunhofer institutesensure that research projects achieveresults that can be relied on. Our insti-tutes are equipped with up-to-datelaboratory technology, making themattractive to companies of all sizes andfrom all industrial sectors. As a strongcommunity, we can provide our part-ners with reliability and economicbenefits: the Fraunhofer-Gesellschaftcan bring the knowledge already gained from cost-intensive preliminaryresearch into joint projects.

Research Facilities in Germany


The Fraunhofer-Gesellschaft at a Glance

Jointly shaping the future

The RWTH Aachen University Chairsfor Laser Technology LLT and the Tech-nology of Optical Systems TOS, alongwith the study and research depart-ment for the non-linear dynamics oflaser production methods NLD, repre-sent an outstanding cluster of exper-tise in the field of optical technologies.This permits supercritical treatment ofbasic and application-related researchtopics. The close cooperation with theFraunhofer Institute for Laser Technolo-gy ILT not only permits industrial con-tract research on the basis of soundfundamental knowledge, but also pro-vides new stimuli for the advanceddevelopment of optical methods, com-ponents and systems. The synergy ofinfrastructure and know-how is put toactive use under a single roof.

This structure particularly benefits up-and-coming young scientists and engi-neers. Knowledge of current industrialand scientific requirements in the opti-cal technologies flows directly into theplanning of the curriculum. Further-more, undergraduates and postgradu-ate students can put their theoreticalknowledge into practice through pro-ject work at the Fraunhofer ILT. Univer-sity courses are drawn up jointly aswell. The interdisciplinary collaborationbetween physicians and engineers, forinstance, has resulted in a universityseminar for advanced dental trainingbeing set up. Teaching, research andinnovation – those are the bricks withwhich the three university departmentsand the Fraunhofer ILT are building thefuture.

Chair for Laser Technology LLT

The department of laser technology atRWTH Aachen has been engaged inapplication-oriented research anddevelopment in the fields of micro,thin film, surface and x-ray technologyand in integrated optics since 1985.Laser beam sources with short pulsedurations of between 10-13 and 10-3

seconds are employed in the microstructuring of materials by ablationand modification. Applications includethe drilling of holes in metal for aero-space engineering and the processingof glass by changing the index ofrefraction.

Pulsed laser deposition is used to pro-duce thin coatings for wear protection,electronics, integrated optics andmedical engineering applications. Coating with laser beams makes itpossible to produce complex multi-component materials with controlledfilm structures.

Laser-beam deposition welding is usedin wear and corrosion protection,maintenance and the production of 3Dcomponents. The chief customers aremechanical engineering, tool manufac-turing and engine building companies.

ContactProf. Dr. Reinhart Poprawe M. A.Phone: +49 (0)241/8906-109Fax: +49 (0)241/8906-121 [email protected]


Laser Technology at RWTH Aachen

Chair for the Technology of Optical Systems TOS

By establishing the Chair for the Tech-nology of Optical Systems in 2004,RWTH Aachen accorded recognition tothe increasingly central role of highlydeveloped optical systems in manufac-turing, the IT industries and the lifesciences. Research activities focus onthe development and integration ofoptical components and systems forlaser beam sources and laser devices.

Highly corrected focusing systems for a high laser output, beam homogeni-zation facilities and innovative beamshaping systems are all key compo-nents of laser systems used in produc-tion engineering. The performance of fiber lasers and diode-pumped solid-state lasers, for instance, is determinedby optical coupling and pump lighthomogenizers. Waveguide structuresfor frequency conversion are yet an-other topic of research. In the area ofhigh-power diode lasers, micro- andmacro-optical components are deve-loped and combined to form completesystems. In addition, assembly tech-niques are optimized.

ContactProf. Dr. Peter LoosenPhone: + 49 (0)241/8906-162Fax: +49 (0)241/[email protected]

Study and research departmentfor the non-linear dynamics of laserproduction methods NLD

Founded in 2005, the study and re-search department for the non-lineardynamics of laser production methodsNLD complements the system-orientedR&D activities of the LLT and TOS de-partments.

The goal of non-linear dynamics is to investigate technical systems bymathematical, physical and experimen-tal means and to make these researchfindings available for industrial production and teaching purposes.

Solving equations to determine thecontinuum limit in physical systemsmakes it possible to analyze flow patterns in process gases and moltencharges that constitute boundary layers, for instance. It is only throughsimulation and modeling, moreover,that thermal radiation during weldingcan be diagnosed.

The application of mathematicalmodels not only makes it easier tounderstand dynamic processes, butactually gives rise to entirely new pro-duction engineering concepts. Thanksto the close cooperation with theFraunhofer ILT, the insights gained canbe directly implemented in industriallaser materials processing. As an ex-ample, online monitoring systems aresystematically expanded and adaptedto meet practical needs.

ContactProf. Dr. Wolfgang SchulzPhone: +49 (0)241/8906-204Fax: +49 (0)241/[email protected]


Laser Technology at RWTH Aachen

Cluster of Excellence

In the Cluster of Excellence »Integra-tive Production Technology for High-Wage Countries«, for which DFG funding was approved in October 2006,process engineers and materials scien-tists based in Aachen are developingnew concepts and technologies offer-ing a sustainable approach to industrialmanufacturing.

A total of 18 chairs and institutes of RWTH Aachen, together with theFraunhofer Institutes for Laser Techno-logy ILT and for Production TechnologyIPT, are working on this project, whichin the first instance will run until theend of 2011.

Funding of approx. 40 million euroshas been granted to this Cluster ofExcellence, an initiative that unites thelargest number of research groups inEurope devoted to the objective ofpreserving manufacturing activities inhigh-wage countries.

Production in high-wage countries

The competition between manufac-turers in high-wage and low-wagecountries typically manifests itself as a two-dimensional problem, opposingproduction efficiency and planningefficiency.

In each case there are divergent ap-proaches. With respect to productionefficiency, low-wage countries tend to focus exclusively on economies ofscale, whereas high-wage countriesare obliged to seek a balanced equili-brium between scale and scope, inother words being able to satisfy cus-tomer requirements in respect of a particular product while at the sametime attaining a minimum productionvolume.

A similar divergence is evident with res-pect to the second factor, that of plann-ing efficiency. Manufacturers in high-wage countries aim to continuouslyoptimize their processes, using corres-pondingly sophisticated, capital-intensiveplanning methods and instruments, and technologically superior productionsystems. In low-wage countries, by contrast, production needs are betterserved by simple, robust, supply-chain-oriented processes.

In order to maintain a sustainable com-petitive advantage for production sitesin high-wage countries, it is no longersufficient to aim for a better positionthat maximizes economies of scale and scope or reconciles the opposingextremes of a planning-oriented and avalue-oriented approach. Instead, thegoal of research must be to cancel outthese opposite poles as far as possible.Ways must be found to allow a greatervariability of products while at thesame time being able to manufacturethem at cost levels equivalent to massproduction. This calls for value-optimizedsupply chains suited to each product,without excessive planning overheadsthat would compromise their cost-effectiveness.

Tomorrow’s production technologytherefore requires a thoroughly newunderstanding of these elementary,interrelated factors.

Integrative production

The Cluster of Excellence »IntegrativeProduction Technology for High-WageCountries« is aiming for the long-termgoal of increasing the competitivenessof German production technology. Theoverarching hypothetical solution liesin achieving the next higher level ofproduction integration.


Cluster of Excellence »Integrative Production Technology for High-Wage Countries«

The production dilemma: Scale/scopevs. planning-oriented/value-oriented,source: WZL Aachen.

Individualized production

Individualized production involves allowing for a high degree of productvariability and dynamics at costs equi-valent to those of mass production.Concepts are being developed that willenable the optimum combination andconfiguration of the different elementsin a production system to be identified.At the same time, advanced manufac-turing technologies such as selectivelaser melting (SLM) are being furtherrefined, and will eventually enableone-piece-flow concepts to be imple-mented at the same costs as mass production.

Virtual production

The introduction of greater flexibility inproduction processes necessarily resultsin an increased volume of preparatoryand planning activities. In the clusterdomain Virtual Production Systems,the aim is therefore to improve plann-ing quality while simultaneously re-ducing the quantity of work involved.This is being done by developing dis-crete models representing, for instance,laser welding processes and materials,linking them together and integratingthem in a virtual supply chain.

Hybrid production

By integrating a number of discreteprocesses in a single hybrid process, it is possible to reduce the length ofsupply chains and hence organizethem more efficiently. In the clusterdomain Hybrid Production, methodsare being investigated that will enablesupply chains to be systematicallyhybridized, and hybrid technologiessuch as laser-assisted incremental sheetforming are being developed.

Self-optimizing production

Self-optimization is a way of optimiz-ing production processes withoutincreasing the volume of upstreamplanning activities. In the clusterdomain Self-optimizing Production,methods and technologies are beingdeveloped to increase the cognitivecapabilities of production systems suchas a laser cutting plant or an assemblysystem for optical components.

Contacts

Fraunhofer ILTDipl.-Phys. Christian Hinke Phone: +49 (0)241/[email protected]

Cluster of Exellence Office Dr. Frank Possel-DölkenPhone: +49 (0)241/[email protected]


Cluster of Excellence »Integrative Production Technology for High-Wage Countries«

The official opening of theCluster of Excellence in October2006, source: WZL Aachen.

Source: WZL Aachen.

Short Profile

PhotonAix, the Competence Networkfor Optical Technologies and Systems,was founded in 2002 by the Fraun-hofer Institute for Laser Technology ILT,the Fraunhofer Institute for ProductionTechnologies IPT and the Laboratory of Machine Tools and ProductionEngineering WZL of the RWTH Aachen.Aachen-based PhotonAix and eightother regional competence networksmade up of more than 400 membersfrom research and industry are concen-trating their skills with the mutual goalof promoting optical technologies intheir respective regions.

These competence networks representthe full range of »Made in Germany«optical technologies, from laser-basedmaterials processing and biophotonicsto transportation and aerospace appli-cations. The networks are primarilyengaged in providing services such as technology management, start-upconsulting, regional technology andindustry marketing, quality trainingand education initiatives, and fosteringcommunications within the network.The regional concentration of expertiseleads to practical, real-time problemresolution and an accelerated transferof research results into market-readyproducts.

Highlights 2006

Besides participating in Photonics West2006 in San Jose, USA, and Optatec2006 in Frankfurt as a joint exhibitorwith the other German competencenetworks for optical technologies, themajor event of 2006 was the establish-ment of the European technology plat-form Photonics21. Following the for-mal acceptance by Brussels of theproposal to create the technology plat-form in December 2005, PhotonAixwas heavily involved in the drafting ofa Strategic Research Agenda.

The Strategic Research Agenda entitled»Towards a Bright Future for Europe«,which will form the basis for collabora-tive research on optical technologies inEurope, was submitted to the Commis-sioner for Information Society andMedia, Viviane Reding, in April 2006.

Seven thematic workshops (on Infor-mation and Communication, IndustrialProduction/Manufacturing and Quality,Life Sciences and Health, Lighting andDisplays, Metrology and Sensors,Design and Manufacturing of Compo-nents and Systems, Photonics Researchand Education and Training) were held in December 2006 to identifyappropriate themes for future researchprojects.

Contact

PhotonAix e. V.Dipl.-Phys. Christian HinkeManaging directorSteinbachstraße 1552074 Aachen

Phone: +49 (0) 241/8906-352Fax: +49 (0) 241/[email protected]


PhotonAix e. V.Competence Network for Optical Technologies

Professor Reinhart Popraweamong the members of theBoard of Stakeholders of theEuropean technology platformPhotonics21.

Laser and Plasma Sources

This business area encompasses thedevelopment of diode laser modulesand systems as well as diode-pumpedsolid-state lasers with different reso-nator structures (stab,slab,fiber), the design of new diode laser structures,the microassembly of diode lasers and optical components, and the develop-ment of plasma systems.

For more than 10 years spinn-offs ofthe Fraunhofer ILT are set up in the framework of some projects. In coope-ration with the Fraunhofer IAF newstructures are being designed whichpermit the manufacture of diode lasersdemonstrating higher beam quality. The business area continues to enjoy a unique reputation in the assembly of high-power diode lasers and in particular the installation of automatedassembly and test facilities. Work inthe plasma technology sphere focuseson the development of EUV beamsources for semiconductor lithography.The main target markets for the busi-ness area as a whole are laser machining,medical engineering and metrology,along with the component market forinformation and communications tech-nology.


Business AreaLaser and Plasma Sources

Direct generation of pulsed laser beams at 935 nm withmixed-garnet crystals.

Visualization and optimization of flow in microchannel heat sinks 36

Assembly of diode laser bars usinggold-tin vapor deposition 37

Emitter-resolved characterization of diode laser bars 38

Characterization facility for collimated and uncollimated diode lasers 39

Pump module for frequency doubling of 405 nm wavelength 40

Raman pump source with 4 wavelengths based on high-powerdiode lasers 41

Fiber-coupled diode laser beam source of high spectral and spatial brilliance 42

Fiber-coupled diode-laser pump module for the BepiColombospace probes 43

Development of homogenization optics for a bichromatic diode laser 44

Q-switched Nd:YVO4 oscillator on a customer-specific platform 45

Frequency-stabilized pulsed lasers for aerospace LIDAR applications 46

A highly efficient laser pulse source for satellite-based atmospheric research with LIDAR 47

Diode-seeded fiber amplifier for LIDAR applications 48

Direct generation of pulsed laser beams at 935 nm with mixed-garnet crystals 49

Ultra-stable single-frequency oscillator-amplifier configuration with high average output power 50

Numerical modeling of ytterbium-doped slab amplifiers 51

Computation of unstable resonators for laser altimeters 52

Fiber-integrated base module for multi-kilowatt fiber lasers 53

Numerical simulation of non-linearthree-wave coupling in waveguidestructures 54

Beam source delivering wavelengths in the water window region for X-ray microscopy 55

EUV microscopy for defect inspection on surfaces and thin films 56

Energy monitor for extreme ultraviolet radiation 57

Simulation of laser-induced vacuum discharge 58

Note from Institute DirectorWe would like to point out that the publicationof the following industry projects has beencoordinated with our customers. In principle,industry projects are subject to the strictestobligation to maintain secrecy. We would liketo take this time to thank our industrial partnersfor their willingness to have their reports listedpublished.


Contents

Task

Microchannel heat sinks for diode lasershave a limited service life because theyquickly exhibit signs of wear. Erosion bythe cooling medium as a result of turbu-lence and separation zones in the heatsink is one limiting factor. Excessively highlocal temperatures due to inefficient cool-ing in the microchannels can also result in premature failure of the diode laser. Vi-sualization of these problem zones helpsto identify vulnerable areas in a heat sink.Any necessary changes to the design orthe boundary conditions are checked bymeans of FEM calculations.

Method

Particle Image Velocimetry (PIV) is anon-contact optical measuring tech-nique that enables quantitative andqualitative statements to be madeabout flow properties in complex geo-metries. Particles admixed with the water make it possible to visualize theflow using PIV. The particles are illumi-nated by laser in a certain plane, afterwhich a series of digital images is madein quick succession. A software pro-gram evaluates the images and gene-rates a vector-based flow diagram. The results thus obtained are comparedwith flow simulations (CFD). Designimprovements are made in the criticalareas and verified with the aid of furthersimulations. A more efficient coolingperformance can also be achieved byadapting boundary conditions such asflow velocities.

Results and Applications

PIV measurements carried out on a 2:1 model of a heat sink reveal distinctareas of turbulent flow in the vicinityof channel inlets. The measurementsclearly show the effect of the flow ve-locity on the formation of boundary-layer flow patterns in the microchan-nels. The different throughput in theindividual channels can also be dis-cerned. Varying the flow velocity causesthe boundary-layer flow in the chan-nels to enlarge to different extents.This results in a less than optimumcooling performance, because parts of the channel wall are not in contactwith the flow and therefore cannotdissipate any heat. Design changes arebeing made to the heat sink to rectifythis situation. CFD simulations help to adapt the geometry and directly visualize the effect on cooling perfor-mance.

Contact

Dipl.-Ing. M. Leers, Tel.: [email protected]. K. Boucke, Tel.: [email protected]


Visualization and optimization of flow in microchannel heat sinks

Above: Visualization of flow velocities using PIV.Middle: Magnified image of the flow pattern at the tip of a microchannel.Below: Result of flow simulations at the inlet to the microchannels.

Task

Conventional heat sinks for diode la-sers are made of copper. The laser barsare mounted with a soft solder mate-rial, usually indium. One of its functionsis to compensate for the different coefficients of thermal expansion po-ssessed by the heat sink and the laserbar. Particularly in pulsed operation,these soldered bonds do not always remain stable for long periods.

Compensation with soft solder is notrequired if the heat sinks used are matched to the thermal expansion pro-perties of the laser bars. In this case,hard solders that remain stable overlong periods such as eutectic gold-tinalloy (AuSn) can be used. The solder is provided either as a preform or as alayer applied to the heat sink. A process for vapor deposition of eutectic AuSnsolder layers was developed in the con-text of a project at the Fraunhofer ILT.

Method

The vapor deposition of the solder onthe heat sinks is carried out in a highvacuum using two vaporizers for thebasic materials of gold and tin. Para-meters such as the quantity of materialto be vaporized, the vapor depositionrates and the order of the layers arevaried in order to create the necessarylayer thicknesses and the overall com-position. Dome-shaped sections arecut in order to verify the correctstructure of the individual layers usingREM and EDX. This is followed by re-flow tests to determine the behavior ofthe solder during the process and theliquidus temperature. The compositionof the solder can be determined byexamining the melted samples.


An EDX analysis of the solder’s stoichio-metrical composition confirms the re-quired mass ratio of 80 percent gold to20 percent tin. At the same time, solder-ing tests reveal flawless wetting of thesolder.

The optical performance data of laserbars assembled on heat sinks with matched thermal expansion using gold-tin solder are not different from those of indium-soldered bars. Investigationshave shown that the stresses induced in the laser bar are minimal. One of the main causes of the previously expe-rienced aging deterioration has thusbeen eliminated. The combination ofheat sinks with matched thermal expan-sion and gold-tin soldering of the laserbars means that a long service life canbe expected.

Contact

Dipl.-Ing. M. Leers, Tel.: [email protected]. K. Boucke, Tel.: [email protected]


Assembly of diode laser bars using gold-tin vapor deposition

Above: Dome-shaped sectionthrough a laser bar assembledusing gold-tin solder.Below: Laser bar mounted on aheat sink with matched thermalexpansion using gold-tin solder.

Laser bar AuSn

WCu

nickel

100 µm

Task

To obtain a more detailed analysis ofthe packaging and aging of diode laserbars, a test bench that enables emitter-resolved measurements is required.The purpose of this test bench is tomeasure laterally resolved intensity,wavelength and polarization distribu-tions reliably and with as few adjust-ments as possible. This information allows the packaging layout and alsothe aging to be analyzed and qualifiedfor each emitter. The wavelength dis-tribution reflects the temperature dis-tribution. The polarization distributionprovides information about the inter-nal mechanical stress in the laser bar.

Method

The test bench maps the emission facet of the laser bar onto a CMOS camera. The lens is so designed that it possesses a wide depth of focus, in order to minimize the adjustmentsnecessary for each separate measure-ment. Attenuating elements enablethe laser bar to be measured both above and below the laser threshold.The camera images and the test benchare analyzed and controlled by a soft-ware program.

The relative intensity distribution, theposition of the emitters and thus the“smile” can be determined in the basicconfiguration. The polarization degreeof the emitters can be determined byinserting a polarization filter into thebeam path. A laterally resolved wave-length spectrum is mapped onto thecamera via a grid positioned in the beam path.


The test bench constitutes an extensionof the semiautomatic electro-opticalcharacterization facility. It has madeemitter-resolved intensity and polariza-tion measurement a standard compo-nent of characterization.

The position of the emitter focal pointsin fast-axis (smile) can be measuredwith a resolution of 0.4 µm. The emit-ter spectra are determined with a rela-tive resolution < 0.2 nm, enabling late-ral temperature variations < 1 K to bedisplayed. The degree of polarizationof individual emitter beams is deter-mined with an error rate of < 1 %.

Since the measurement is performedsimultaneously for all emitters, time-resolved measurements are possible,for instance during pulsed operation of the diode laser.

Contact

Dipl.-Phys. T. Westphalen, Tel.: [email protected]. K. Boucke, Tel.: [email protected]


Emitter-resolved characterization of diode laser bars

Above: Layout of the test bench.Below: Smile, wavelength andpolarization measurement.

po

lari

zati

on

deg

ree

wav

elen

gth

[nm

]sm

ile[µ

m]

emitter

Task

There are many applications where it is important to know the radiationcharacteristic of the diode lasers em-ployed. The task is therefore to deve-lop a facility that can be used for com-plete, automated characterization ofhigh-power diode lasers and stacks.The following optical and electro-opti-cal properties are to be determined ina single series of measurements:• Beam divergence angle (in fast

and slow axis)• Wavelength• PUI characteristic

The diode lasers to be measured can be actively or passively cooled and either collimated or uncollimated.

Method

To determine the beam divergence angle in fast axis direction, the diodelaser is revolved around a rotationalaxis, and to determine the beam diver-gence angle in slow axis direction theemitted beam is deflected with the aidof a scanner mirror. The angle-depen-dent intensity is registered by a photo-diode whose distance from the diodelaser can be varied. This means thatboth collimated and uncollimated diodelasers can be measured.

To measure the wavelength of diodelaser stacks resolved into individualbars, the stack is moved past an adju-stable aperture. The laser beam impin-ges on a detector which is connectedto a spectrometer via an optical wave-guide. The relative motion of the diodelaser with respect to the aperture en-ables the output and a wavelength dis-tribution across the stack to be deter-mined. To measure the PUI characteris-tic the diode laser is moved directly infront of a thermal measuring head.


The characterization facility is suitablefor measuring both diode laser bars andwhole stacks. The measurements canbe performed in continuous or pulsedoperation. The maximum operating current is 150 A for cw operation and200 A for qcw operation, and the maxi-mum operational voltage is 25 V. Pulselengths of 400 µs to 20 ms can be tes-ted in pulsed operation. Beam diver-gence angles of up to ± 60° with aresolution < 0.2 mrad can be measuredin the fast axis, and beam divergence angles of up to ± 15° with a resolution< 5 mrad can be measured in the slowaxis. The beam divergence angle is determined by the FWHM, 1/e2 or the95 percent method. The wavelengthmeasurement resolved into individualbars is carried out with a spectrometerin a range from 780 to 1000 nm with a resolution of 0.25 nm. The thermalmeasuring head is capable of measuringa total output of up to 1 kW.

Contact

Dipl.-Ing. (FH) K. Wieching, Tel.: [email protected]. K. Boucke, Tel.: -132 [email protected]


Characterization facility for collimated and uncollimated diode lasers

Above: View of the overall facility with PC workstation(left) and optics box (right).Below: Detailed view of thethree-part measuring setup (beam initial divergence angle,wavelength and PUI measure-ment).

Task

The first diode lasers with a wave-length of 405 nm are now commercial-ly available, but their maximum CWoutput of approximately 50 mW is stillrelatively low. Higher output values canbe achieved by applying the principleof frequency doubling, in which a crys-tal is pumped at a wavelength of 810nm so that it will emit 405 nm afterfrequency conversion. Taking a taperedamplifier as the basis, the task was todevelop a frequency-stabilized pumpmodule with as narrow a bandwidth aspossible and close to diffraction-limitedbeam quality, whose output power is > 2 W and whose wavelength can befreely adjusted within a range of ap-prox. 10 nm.

Method

To stabilize the frequency of the taperedamplifier, the emitted beam is collima-ted on the back side by an asphericallens. The beam falls on a blazed grating,positioned in the Littrow configuration.Depending on its angle of inclination,a certain wavelength is refracted backinto the laser, thus building up an ex-ternal resonator. On the front side, thelaser beam is collimated by a rotation-symmetrical aspherical lens in fast axisand subsequently by a cylindrical lensin slow axis to compensate for theastigmatism. To ensure a high longi-tudinal mode stability, the resonatorlength must not vary by more than λ/2(400 nm) as a result of thermal influ-ences. To ensure that this is the case,the laser is temperature-regulated andall resonator components susceptibleto thermal expansion are made of silica glass, which possesses a very low coefficient of thermal expansion of only ≈ 0,5 x 10-6/K (at 20°C).


With an operating current of 5 A, the module delivers an optical outputpower in excess of 3 W. The wave-length can be varied between 787 and803 nm by changing the position ofthe grating at a cooling temperature of18°C. The spectral width of the emit-ted light was measured as < 0.1 nm(intensity at 1/e2).

The frequency tuning range can beadapted to the respective requirementsby selecting the most suitable taperedamplifier and by varying the operatingtemperature.

Contact

Dip.-Ing. M. Haverkamp, Tel.: [email protected]. K. Boucke, Tel.: [email protected]


Pump module for frequency doubling of 405 nm wavelength

Structure of the pump module.

Task

In contrast to doped-fiber amplification,Raman amplification produces loweramplifier noise and higher amplification,and opens up further amplificationbands besides the C-band and the L-band. This means that Raman am-plifiers are of great interest to the telecommunications market for signaltransmission over long fiber-opticroutes.

In order to generate a flat amplificationspectrum with a width of 100 nm, for example, multi-wavelength pumpsources are needed. These are built either on the basis of fiber lasers or onthe basis of high-power diode lasers.Multi-wavelength Raman pump sour-ces (MWRP) based on fiber lasers havethe drawback that it is not possible toadjust the output of individual wave-lengths without affecting the outputsof other wavelengths, and their relativeintensity noise is greater than in high-power diode lasers. As a result, the only feasible way of pumping is in theopposite direction to the signal. Theaim of this project is therefore to deve-lop a high-output MWRP based onhigh-power diode lasers.

Method

Since Raman amplification increasesexponentially with the pump output,and the output of diode lasers is limi-ted due to inherent properties, a highlyefficient way of coupling the pump la-sers in single-mode fibers (SMF) is nee-ded. The optical construction tested inthe laboratory was successfully trans-formed into a laser module, making itpossible to achieve a coupling efficien-cy of > 80 % in the module whenusing single-mode lasers in conjunctionwith aspherical lenses of short focal

length. This corresponds to an outputof 400 mW in the SMF at a wave-length of 1426 - 1480 nm. Four fre-quency-stabilized modules are integra-ted in a pump source prototype usingfiber Bragg gratings at wavelengths of 1426 nm, 1435 nm, 1444 nm and1480 nm. Thanks to the grating, theamplification spectrum is not depen-dent on the temperature or the diodeoperating current. The four wave-lengths are coupled in a SMF with the aid of a fusion coupler, thus gene-rating an optical pump output of 1.1 W on 4 wavelengths. The entirepump source is housed in a 19’’ plug-in module.


With a CW signal output of -3 dBm, a fiber length of 52.8 km SMF and apump output of 1.1 W running counterto the signal direction, the new MWRPdelivers an amplification spectrum of 60 nm in the C-band (1520 nm -1580 nm) with 12 dB on/off amplifi-cation, an optical signal-to-noise ratioof 43 dB and a flatness of < 1.5 dB. In contrast to Raman fiber lasers, theMWRP developed is also capable ofpumping in the same direction as thesignal.

The results demonstrated were achievedin a joint project by the Fraunhofer In-stitutes HHI, IAF and ILT.

Contact

Dipl.-Ing. M. Haverkamp, Tel.: [email protected]. K. Boucke, Tel.: [email protected]


Raman pump source with 4 wavelengths based on high-power diode lasers

Above: On/Off amplification in the C-band for signals withan output of -3 dBm.Below: Raman pump source.

on

/off

amp

lific

atio

n

wavelenth

Task

Fiber-coupled diode lasers with opticaloutput powers in the multi-kilowattrange are increasingly competingagainst solid-state lasers as a direct beam source for materials processing.A novel spectral beam superpositiontechnique provides the brilliance of alamp-pumped solid-state laser.

Method

The brilliance of diode lasers is increasedby spectral superposition of individualbeam sources. The state of the art is to use dielectric filters for beam super-position. This method requires a gap of 20 nm to 30 nm between the diodelaser wavelengths, thus only permittinga limited number of beams to be super-imposed in the wavelength range of high-power diode lasers. Current developments in this area build on wavelength stabilization and spectralsuperposition with volume diffractiongratings to increase brightness. Theemission bandwidth of a diode laser is reduced, and the laser beams areselected and superimposed with theircenter wavelengths very close together.

The diode lasers are stabilized at 908 nm,911 nm, 975 nm and 978 nm respec-tively. With volume diffraction gratings,this fourfold spectral superposition is carried out at a center wavelengthspacing of 3 nm.


A fiber with a diameter of 600 µm isused to generate a laser beam outputof 952 W within a numerical apertureof 0.175 (95 % power inclusion). Thespectrum of the wavelength-stabilizeddiode laser features narrowband emis-sion of the four center wavelengthswithin a spectral width of less than 1 nm in the entire power range.

Owing to its spatial brilliance, the diode laser is suitable for directapplications in materials processing,such as the welding of thin-sheet alu-minum. Its high spectral brilliance alsoallows the efficient optical pumping of fiber and solid-state lasers withinnarrowly limited pump bands.

Contact

Dipl.-Ing. C.Wessling, Tel.: [email protected]. H.-D.Hoffmann, Tel.: [email protected]


Fiber-coupled diode laser beam source of high spectral and spatial brilliance

Above: 1-kW diode laser with fiber coupling (fiber diameter 600 µm, housing dimensions 700 x 550 x 220 mm3) and pro-cessing optics (image scale 4:1).Below: Partial view of six wave-length-stabilized diode laser modules with dual beam super-position at a close wavelengthspacing of 3 nm.

Task

In 2012, ESA plans to launch two spaceprobes on an exploratory mission toMercury. The BepiColombo mission willemploy a laser altimeter to produce atopographical map of the planet. Byscanning the surface with this instru-ment and measuring the propagationdelay of the reflected laser pulses, itwill be possible to create a spatially resolved elevation profile of Mercury.The solid-state laser employed by theinstrument will incorporate a fiber-coupled, pulsed pump source, which is being developed on behalf of TESATSpacecom GmbH & Co. KG in Back-nang. Its design has to take into ac-count the special requirements of thisapplication in terms of size, weightand robustness.

Method

In order to obtain the required outputpower, several diode laser bars arejointly coupled into a fiber with a corediameter of 800 µm. Unlike in previousdesigns, this pump module is builtusing a planar arrangement of thebars, which are mounted on individualheat sinks. This enables each bar to be qualified separately and allows theheat to spread more easily than in con-ventional vertical stacks. To shape thebeam for efficient fiber-coupling of thebars, extensive use has been made ofoff-the-shelf components and assem-bly methods used in previously quali-fied cw pump modules that are alreadybeing produced in large volumes. Thiswill simplify the task of qualifying thepump module for use in space applica-tions.


The Fraunhofer ILT has developed theoptical and mechanical design of thepump module, and successfully builtand tested its prototype. During tests,a peak pulse output of 530 W wasachieved at the fiber output. The mo-dule weighs 650 g and measures 150 x 50 x 50 mm. The module's flexibleswitching arrangement allows reliabili-ty to be increased at lower outputpower by means of cold redundancy.The modular structure of the pumpmodule also enables it to be easilyadapted to the requirements of othermissions.

Contact

Dipl.-Ing. M. Traub, Tel.: - [email protected]. H.-D. Hoffmann, Tel.: - [email protected]


Fiber-coupled diode-laser pump module for the BepiColombo space probes

Prototype of the fiber-coupleddiode-laser pump module.

Task

The surface processing of fiber-rein-forced plastic components has so farbeen carried out in a special produc-tion process at the Dutch companyAFPT using high-power diode laserswhose beam shape is not adapted tothe process. The power density distri-bution of commercial diode laser sys-tems leads to undesirable temperaturegradients which, due to local melting,have a negative effect on the results of this application. In an innovativeprocess, a rectangular diode laser beamwith homogeneous power densitydistribution is to be used. This will helpto make the production process moreeconomical and more reproducible.

Method

The beam source employed is a bichro-matic diode laser built by Rofin Sinarwith a maximum output of 2.1 kW.The Fraunhofer ILT has developed flexi-ble beam-shaping optics which providea customized, process-optimizedpower density distribution. This enablesthe lens to be adapted to different beam geometries in order to achieve

an optimum heating process for eachdifferent component geometry. An ex-tremely homogeneous distribution isalso to be generated. Because the ho-mogenization optics, together with thelaser head, are to be fixed onto a robotarm, the system's design has to be ascompact and light as possible. In orderto meet the special requirements of industrial mass production, the opticsmust be hermetically sealed and water-cooled.


A beam-shaping lens system for thespecified diode laser was set up at theFraunhofer ILT and successfully quali-fied in collaboration with the Fraunho-fer IPT and AFPT. This system can pro-vide homogeneous power density dis-tributions in the machining plane withdimensions of 20 mm x 40 mm, 40 mmx 40 mm and 11 mm x 40 mm. Thanksto their size- and weight-optimized design, the optics measure as little as200 mm x 60 mm x 60 mm and weighonly 1450 g. In collaboration with theFraunhofer IPT, the industry-standardbeam-shaping optics were integratedinto the existing installation. The opticshelped to achieve a transfer efficiencyof 90% and a homogeneity of over90%.

Contact

Dipl.-Ing. M. Traub, Tel.: - [email protected]. H.-D. Hoffmann, Tel.: - [email protected]


Development of homogenization optics for a bichromatic diode laser

Beam-shaping optics.

Task

At the request of a customer, a markinglaser was to be integrated in an existinglaser welding system. In order to avoidan expensive retrofit of the given instal-lation, the marking laser had to be setup on a platform whose mechanical,optical and electrical interfaces wereprecisely adapted to the existing system.

Method

The mechanical interfaces of a plat-form developed at the Fraunhofer ILTwere adapted to the existing installationaccording to the customer's specifi-cations.

In order to meet the requirements im-posed on the electrical interfaces, suchas a separate shutter control and ad-ditional interlock circuits, the power supply unit of a commercially available diode laser was modified to suit thecustomer's wishes. In addition, anAOM driver was integrated in thepower supply unit. The marking laser ispumped with a high-power laser diodeand, depending on the selected work-ing point, has an average laser outputof up to 6 W with a good beam qualityin Q-switched mode. The output beamof the oscillator was adapted to thecustomer's processing optics.


The laser was implemented accordingto the customer's specifications. Theresult is a robust, near-production pro-totype. The overall height of the con-trol units, including the water-air coo-ler, is 6 HU. The laser was integratedinto the existing system.

The available platform can be employedfor a variety of applications, and is cur-rently being used as a base for settingup a UV source.

Contact

Dipl.-Phys. D. Esser, Tel.: [email protected]. H.-D. Hoffmann, Tel.: [email protected]


Q-switched Nd:YVO4 oscillator on a customer-specific platform

Near-production prototype of an Nd:YVO4 oscillator.

Task

High-resolution measurements of windspeeds or the concentration of gasessuch as water vapor, methane and CO2

in the atmosphere using LIDAR (LightDetection And Ranging) require highlystable narrowband laser pulses withpulse energies in the range of 10 - 100mJ and bandwidth-limited pulse dura-tions in the range of 10 - 100 ns. Theseare normally generated by seeding aQ-switched laser with a highly stablelow-power narrowband laser sourcewhile actively stabilizing the resonatorlength.

Systems used in laboratories, wherethere is little mechanical interference,the so-called pulse-build-up controlprocess is often used, which can onlysuppress mechanical oscillations belowthe pulse repetition rate.

The systems required for aerospace applications have a pulse repetition rateof 100 Hz and must ensure frequency-stable operation even in the presenceof parasitic oscillations in the kHz range,with amplitudes of changes in the re-sonator length in the range of severaltens of nanometers.

Method

The researchers are developing entirelypassively cooled, Q-switched funda-mental-mode oscillators with a high efficiency and low sensitivity to misa-lignment and temperature fluctuations.These characteristics are to be achievedby means of a compact structure incombination with a fault-tolerant reso-nator design.

The methods being developed to ad-just the resonator length are based onmeasurements of the seed signal andenable the suppression of mechanicaloscillations up to the multi-kHz range.


The resulting oscillators achieve pulseenergies of 12 mJ and M2 < 1.1 duringseeded and frequency-stabilized ope-ration with a pulse repetition rate of100 Hz and a pulse duration of 30 ns.Within a temperature range of 12 °C,their pulse energy fluctuates by lessthan two percent.

The 'Ramp-Delay-Fire' control processdeveloped by the researchers enables a frequency stability of < 1 MHz (rms),a pulse bandwidth of less than 8 MHz(FWHM) and an exceptionally high fre-quency stability even under the influ-ence of major disturbances to the reso-nator length. At a parasitic frequencyof 1.05 kHz and an amplitude of 160nm, for example, a frequency stabilityof 3 MHz (rms) is recorded, while at320 nm the stability lies at 8 MHz. Incontrast to previously used methods, itis still possible under these circumstan-ces to predict the pulse emission accu-rately to within just a few nanose-conds.

Contact

Dipl. Phys. K. Nicklaus, Tel.: [email protected]. Ing. H.-D. Hoffmann, Tel.: [email protected]


Frequency-stabilized pulsed lasers foraerospace LIDAR applications

Laboratory setup of a passivelycooled, frequency-stabilized oscillator with a piezo-actuatorfor active length adjustment.

Task

Spatially resolved measurements ofconcentrations of molecules (such aswater vapor or carbon dioxide) or ae-rosols in the atmosphere using LIDAR(Light Detection And Ranging) requirehighly stable, narrowband, short laserpulses of high energy. The key criteriawhen selecting a suitable laser sourcefor satellite-based operation are thatthe system be reliable and efficient,and of a compact and light design.

As part of a project currently being im-plemented together with EADS ASTRI-UM to design a 'pre-development mo-del', a laser source is being developedwhich generates laser pulses with anenergy of at least 70 mJ and a wave-length of 1064 nm at a repetition rateof 100 Hz. These laser pulses are thentripled in frequency with the help ofnonlinear crystals. The system shouldbe capable of operating in space for atleast 3 years.

Method

A Q-switched, stable resonator with adiode-pumped Nd:YAG rod serves asthe laser oscillator. Pulse generation isfrequency-stabilized with the help of a seed laser. This enables laser pulseswith an energy of 8 mJ to be genera-ted in excellent spatial and temporalquality.

Downstream of this is a diode-pumpedNd:YAG amplifier operating accordingto the InnoSlab principle, which ampli-fies the laser pulses to 70 mJ withoutsacrificing quality. Given that the slabamplifier largely determines the effi-ciency of the overall system, a series ofdetailed simulations was carried out toestablish the ideal geometry of the la-

ser crystal and the beam path. Any parasitic effects competing against theamplification of the laser pulses are mi-nimized. The special geometry of theInnoSlab laser provides the ideal basisfor this task and also renders the systeminsensitive to ageing of the pump diodesand temperature fluctuations.


Successful tests with the laser oscillatorwere followed by a series of experi-ments to optimize the amplifier. Thesetests were carried out using a flexiblelaboratory setup which will later betranslated into a compact design thatclosely corresponds to the actual di-mensions of the final laser system. Aspecial feature of this design is that itincorporates redundant pump diodesto compensate for diode failures with-out affecting the overall performance.

Cascaded amplifier stages featured inthe design provide an excellent meansof scaling to higher pulse energiessuch as those required, for example, in LIDAR systems used for molecule detection.

Contact

Dipl.-Phys. J. Luttmann, Tel.: [email protected]. H.-D. Hoffmann, Tel.: [email protected]


A highly efficient laser pulse source for satellite-based atmospheric research with LIDAR

Preliminary design of the satellite-based laser source (explodeddiagram).

Task

Pulsed LIDAR systems emit short laserpulses and can determine the distanceto diffusely scattering objects by measur-ing the signals' time delay. The perfor-mance potential depends directly on thelaser system itself. The repetition rate(approx. 0.5 to 2 MHz) is defined by thenumber of measuring points required ina given time period. The maximum rangeof the measuring instrument is prede-termined by the pulse peak output(greater than 1 kW) in connection withthe beam quality (M2 < 1.5). Temporalproperties such as pulse duration andjitter determine the achievable accuracy.

As part of an internal Fraunhofer pro-gram, the ILT is currently developing afiber laser system for scan-based dis-tance measurement together with theFraunhofer IPM.

Method

In order to meet high demands on tim-ing, i.e. pulse durations in the sub-nsrange with low pulse jitter combinedwith the necessary pulse peak outputsin the kilowatt range and average out-puts of several watts, the laser must bedesigned in an oscillator-amplifier con-figuration. The temporal and spectralproperties of the laser pulse are deter-mined by a pulsed laser diode, whosesignal then runs through a two-stagefiber amplifier arrangement. Fiber am-plifiers have several advantages overlaser-rod amplifiers:• They do not need adjustment.• The beam parameters are not

influenced by the power setting.• A high amplification and efficiency

can be achieved.


The laser properties required for the given application were demonstratedin the laboratory. The next step is to in-tegrate the fiber optics into a housingand equip them with the necessarycontrol electronics.

Other possible areas of application for this laser system are measurementtechnologies with temporally shapedlaser pulses, micro-material processingor laser-beam drilling.

Contact

Dipl.-Phys J. Geiger, Tel.: [email protected]. H.-D.Hoffmann, Tel.: [email protected]


Diode-seeded fiber amplifier for LIDAR applications

Above: Laboratory setup of the fiber amplifier.Below: CAD drawing of the laser module.

Task

In order to carry out satellite-basedmeasurements of climate-relevant watervapor distributions with LIDAR/DILARsystems, the running time-dependentabsorption of single-frequency pulsesis measured. The most suitable wave-lengths for such measurements lie inthe range of 935 - 936 nm and arecurrently generated with titanium-sap-phire lasers or optical parametric oscil-lators, which are characterized by lowefficiencies and high complexity. Alter-natively, this wavelength range can be generated directly in a new type of mixed-garnet crystal. By varying thegarnet composition of the crystal me-dium, the energy levels of the Nd ioncan be specifically adapted to the re-quired wavelengths. The University ofHamburg has for the first time success-fully grown Nd:YGG crystals and de-tected laser emissions in cw mode withhigh efficiency at 935 nm. Crystals based on this development are to betested in Q-switched mode.

Method

Cylindrical Nd:YGG laser rods are pumped at both ends in a stable folded resonator assembly with a pulse repe-tition rate of 100 Hz. The system is Q-switched by means of a Pockels cell.


During the experiments in qcw mode,up to 16 mJ was generated with anoptical pump energy of 63 mJ. Thiscorresponds to an efficiency of 25%.With an efficiency of 9%, a pulse energy of 4 mJ was produced for thefirst time in Q-switched mode. Higherenergies are to be generated in futureusing suitable InnoSlab amplifiers.

Given that water vapor largely deter-mines the energy balance in the atmos-phere, robust LIDAR systems withemissions at a wavelength of 935 nmare likely to be employed on mobileplatforms such as aircraft and satellites,but also as ground-based systems.

Essentially, it is being demonstratedthat, by using customized laser crystalsand adapting the laser's design, it ispossible to generate application-speci-fic wavelengths directly and efficientlyfor both test and measurement andmaterials processing.

Contact

Dipl.-Phys J. Löhring, Tel.: [email protected]. H.-D.Hoffmann, Tel.: [email protected]


Direct generation of pulsed laser beams at 935 nm with mixed-garnet crystals

Above: Left: Nd:YGG boulemade by the ILP. The rod-makingmaterial has been removed.Right: Nd:YGG boule made by the FFE.Below: Folded resonator withan Nd:YGG crystal pumped atboth ends.

Task

Metrological and scientific applicationsrequire long-term-stable, low-noiseand extremely narrowband single-fre-quency laser sources with high averageoutput power and diffraction limitedbeam quality. Areas of application in-clude LIDAR (Light Detection And Rang-ing), precision interferometry and thecooling of atoms in atom traps. In non-linear optics, such sources can be usedtogether with external resonators forSHG, DFG and OPO processes. In colla-boration with INNOLIGHT GmbH, theresearchers are developing compactsingle-frequency laser sources with anaverage laser output in the range of 10 - 40 watts.

Method

A diffraction-limited, ultra-stable, nonplanar ring oscillator built by INNO-LIGHT GmbH is amplified from 1 - 2 Wto 40 - 45 W in a multiple-folded con-figuration using an INNOSLAB amplifierstage. The oscillator's excellent beamproperties such as beam quality, polari-zation, spectral bandwidth and low in-tensity noise can be largely preservedin the amplification process.


After the amplifier stage, the followingresults were achieved:• Average output: 45 W• M2: < 1.2• Wavelength: 1064 nm• Emission spectrum: single frequency• Line width: 1 kHz / 100 ms• Tuning range: 30 GHz• Relative intensity noise (RIN):

5 · 10-7 Hz-1/2 (> 10 kHz)

Due to the modular design of the am-plifier stage, both actively and passive-ly cooled laser diodes can be used as a pump source. The amplifier stagecan be scaled to higher output power

Contact

Dipl.-Phys. M. Höfer, Tel.: [email protected]. H.-D. Hoffmann, Tel.: [email protected]


Ultra-stable single-frequency oscillator-amplifier configuration with high average output power

Above: Laboratory model of an oscillator-amplifier unit. Below: Beam profiles after ampli-fier. Above: scaled beam profile infocus. Below: beam profile in farfield.

Task

The suitability of ytterbium-doped lasercrystals as a lasing medium for the ef-ficient operation of end-pumped slab lasers (InnoSlab) is to be investigated in this study. Ytterbium is utilized as a laser-active ion in a whole range ofhost materials. However, in contrast towidely employed 4-level systems (e.g.Neodymium), the interaction betweenpump radiation and laser radiation hasto be taken into account when ytter-bium, a pseudo 3-level system, is usedin diode-pumped solid-state laser sys-tems. This is, for example, because areas with no pump radiation tend toabsorb laser radiation and because ofthe mutual dependence of the localabsorption of pump radiation and laserradiation. Additionally, the inversion of ytterbium-doped host materials, andtherefore also their amplification cha-racteristics, is temperature-dependant.

Method

A software module was employed thatnumerically solves the rate equationsfor cw operation on the assumption ofa thermally relaxed population of theStark-split sublevels of the upper andlower laser levels. This module is inte-grated into a software tool (OPT) thatenables the rigorous propagation ofcomplex electromagnetic waves and isalso utilized in a further program thatenables the propagation of virtuallydiffraction-limited beams by means ofexpansion to higher-order modes. Thepropagation of the pump radiation istaken into consideration in order toestablish the level of amplification inthe laser crystal and recursion is em-ployed to determine the self-consistentspatial distribution of the inversion andthe laser or pump radiation.


With the help of these models, theoverlap between amplification and lasermode in the laser crystal and the degreeof doping in crystals can be optimized.In experimental use, they can provideinsights into the effects of factors suchas seed and pump capacity and the in-ternal temperature of the laser crystalon amplification levels. A suitable diver-gence of the pump radiation in 3-levelsystems can, for example, considerablyincrease the efficiency of a laser by re-distributing the pump capacity in the la-ser crystal from unused areas to areaswith high beam intensity.

In conclusion, software tools are nowavailable with which ytterbium-dopedlaser amplifiers can be numerically opti-mized by simply altering the geometricdata or the boundary values.

Contact

Dipl.-Phys. T. Mans, Tel.: [email protected] Dr. P. Rußbüldt, Tel.: [email protected]. H.-D. Hoffmann, Tel.: [email protected]


Numerical modeling of ytterbium-doped slab amplifiers

Above: Local intensities in anytterbium-doped slab crystal.Below: Intensity distribution ona laser mirror (top and bottom)and on a laser crystal (middle).

crystal

Task

Laser-based altimeters for use in sa-tellites require high pulse energies (50- 100 mJ) and high beam quality (M2

< 1.5). However, they must also be robust and of relatively simple con-struction. In stable resonators with ahigh beam quality, pulse energy is limi-ted to a few mJ, necessitating the useof elaborate MOPA arrangements toachieve the required pulse energy levels.However, in unstable resonators, highbeam quality can be achieved withhigh mode volumes, resulting in highpulse energies. While the design ofstable resonators is generally based onrelatively straightforward ABCD-matrixcalculations, unstable resonators ne-cessitate the use of numerical calcula-tions based on diffraction theory, dueto the lack of any specific analytical so-lutions. These calculations are primarilyemployed to determine the dimensionsof the Gauss-shaped, coated variablereflectivity mirror (VRM) and the levelof magnification.

Method

The OPT software simulation tool developed by the Fraunhofer ILT is apowerful environment for the compu-tation of diffraction theory problems.Intensity and phase distribution of a laser beam are represented in two-di-mensional complex matrices. Propaga-tion and the effects of optical elementssuch as mirrors, lasing media or non-linear crystals are then determined byapplying operators to these matrices.With the help of Fox and Li algorithms,the stable intensity distribution andphase distribution in an unstable reso-nator can be calculated.


Suitably robust resonator configurationswith the necessary beam quality, effi-ciency and sensitivity for use in satellite-based altimeters were identified by car-rying out numerous parameter studies.

Contact

Dipl.-Phys J. Löhring, Tel.: [email protected]. H.-D.Hoffmann, Tel.: [email protected]


Computation of unstable resonators for laser altimeters

Above: Beam profile computedaccording to Fox and Li.Below: Basic layout of an unstable resonator.

pump-light

Q-switch

VRM reflectivity mirror lasing mediumend mirror

Task

An important characteristic of fiber lasers is their ability to generate a dif-fraction-limited beam at average laserpowers of 1 kW or higher. By employ-ing fiber-integrated laser components,rugged, compact setups can be con-structed that allow the fiber laser to be used as a tool for laser materialsprocessing.

Method

Commercially available active fibersand fiber-integrated components, suchas fiber Bragg gratings and fiber coup-lers, were investigated for their suitabi-lity for applications in the output rangeof one kilowatt or more. Optimizedactive laser fibers were developed andtested in collaboration with the Institutfür Photonische Technologie IPHT in Jena, Germany.

A number of pump concepts wereinvestigated with regard to relevantcharacteristics such as preservation ofbeam quality, efficiency, reliability andcost.

A further consideration was the ther-mal management of both active andpassive components; these included laser fibers, fiber couplers and spliceconnections. To this end, measure-ments were performed that enabled tocalculate the heat generated by thesecomponents. The cooling of the com-ponents was then optimized with thehelp of FEM simulation.


The suitability of a variety of fiber typesfor operation in the required outputrange, at a laser output of up to 910 Wand a measured beam quality of M2 =1.04 to 1.3, was investigated.

Basic pump concepts were analyzedand two arrangements were selectedfor further development. These arecurrently being built. On the basis ofthe thermal investigations, a coolingconcept could be developed that is relatively simple to implement andadequately guarantees the long-termstable operation of all the relevantcomponents of a fiber laser with anoutput power of up to 2 kW.

Contact

Dipl.-Phys. J. Geiger, Tel.: [email protected]. B. Zintzen, Tel.: [email protected]. H.-D. Hoffmann, Tel.: [email protected]


Fiber-integrated base module for multi-kilowatt fiber lasers

Above: Fiber laser setup.Middle: Measurement of tem-peratures in an active fiber.Below: Temperature profilethrough the cross-section of afiber when cooled on one sideonly.

Task

A current trend in laser design is thedevelopment of small laser systemsthat rely on waveguide structures toguide propagation, rather than thefree space propagation of radiationfields. This allows considerably smallerdiameters to be employed. Small dia-meters are particularly advantageousfor non-linear coupling processes, be-cause high beam intensities can be ge-nerated with relatively low output le-vels. This is an important prerequisiteto obtaining high power conversion ef-ficiencies. In the case under considera-tion, radiation with a wavelength of2.83 µm is produced from two radiationfields with respective wavelengths of1.5 µm and 0.98 µm by generating adifference frequency. Such systems canbe optimized by analyzing experimentalresults and carrying out simulations.

Method

A software tool was developed to nu-merically simulate difference frequen-cies in periodically polarized non-linearcrystals. This allows the three waves inthe waveguide structure and the non-linear coupling of the three waves tobe analyzed with the help of the splitstep method. Wave propagation is solved by means of semivector appro-ximation using a method based on wide angle beam propagation, and thenon-linear coupling of the three wavesby numerically integrating the couplingequations (4th order Runge-Kutte me-thod). The algorithms are implementedin the Python interpreted programminglanguage with embedded C code being

employed for operations requiring alarge amount of processing capacity.This combination of programminglanguages takes advantage of thespeed of the native compiled C codeand the flexibility of Python.


The input consists of a so-called signalwave at a wavelength of 1.5 µm and apower of 0.4 W, and two pump wavesat wavelengths of 0.98 µm and 0.5 µm.The phase matching condition, whenthe three waves are in phase synchro-nization, is achieved by periodicallyswitching the polarity of the crystal.The accompanying graph shows theoutput throughout the entire length ofthe resulting wave, the so called idlerwave.

Contact

Dr. R. Wester, Tel.: [email protected]. Dr. W. Schulz, Tel.: [email protected]


Numerical simulation of non-linear three-wave coupling in waveguide structures

Output of the frequency-con-verted idler wave. The risingsteps in the output curve corres-pond to the period length of the crystal in successive switching states.

Task

Soft X-ray microscopy has the potentialto open up a wide range of new appli-cations in the fields of biological andmaterials science. High-performanceinstruments require beam sources ca-pable of delivering a brilliance that un-til now has only been provided byelectron-beam storage rings. By deve-loping high-output compact plasmasources, it will be possible to constructlaboratory-scale X-ray microscopes.

Method

On the basis of our experience withpinch plasmas producing 13.5-nano-meter EUV emission, we developed anefficient source capable of producingline emission at 2.88 nanometers fromnitrogen plasma. The gas is ionized bya pulsed voltage and briefly heated toa high temperature. A portion of thisinserted energy is emitted in the formof characteristic soft x-rays.


Measurement of the 1s2-1s2p transitionin helium-like nitrogen at 2.88 nmshowed that the source emitted 1·1014

photons per pulse into the half-space.This corresponds to an energy of about7 mJ. The lateral half-intensity width ofthe plasma lay in the region of 300 µm.Thus, at a discharge frequency of between 1 and 2 kHz, the source issufficiently brilliant to generate photonflows on microscopic samples, similarto those observed using instrumentsconnected to a beam line.

In addition to their use in laboratory X-ray microscopes, the availability of af-fordable compact beam sources operat-ing in the soft x-ray region will permitthe development of a new generationof compact instruments for high-reso-lution surface structuring and analysis.

Characteristics• Spectral range: 1 - 10 nm

depending on process gas• Frequency: 1 - 2 kHz• Brilliance (nitrogen):

1·1017 Ph/(mm2 sr line)• Power input: 10 kW

Contact

Dipl.-Ing. (FH) M. Benk, Tel.: [email protected]. K. Bergmann, Tel.: [email protected]. W. Neff, Tel.: [email protected]


Beam source delivering wavelengths in the waterwindow region for X-ray microscopy

Three-dimensional represen-tation of beam-source intensity (1 pixel represents about 3.7 µm).

Task

Microscopes using extreme ultravioletlight are capable of detecting all typesof defects on a scale of magnitudedown to several tens of nanometers,because of the short wavelength andthe highly efficient interaction withmatter. Many applications, such as themapping of EUV masks for EUV litho-graphy, require an ability to scan largesurfaces for the presence of small prin-table defects as rapidly as possible. Thetechnique of scattered-light measure-ment in the EUV region is well suitedfor this purpose. Through the use of an optical system that both collectsand images light, for instance aSchwarzschild objective in dark fieldmode, and a detector that is sensitiveto EUV light, it is possible to obtain additional information on the positionand size of the defects. The method’sfeasibility has been demonstratedusing the existing laboratory EUV mi-croscope by means of experiments ontest structures with bright-field anddark-field illumination. The apparatuswas characterized with a view toestablishing design parameters and the main characteristics of a system for commercial instruments.

Method

The EUV microscope developed at theFraunhofer ILT, consisting of a xenongas-discharge source, grazing-incidencecollector, sample positioner, multilayer-coated Schwarzschild objective, andEUV-CCD, was adapted for use indark-field mode. A zero-order dia-phragm placed in front of the objectiveprotects the optical path against theincidence of direct light, ensuring thatonly the light scattered by surface de-fects (e.g. particles on the surface of athin film) will be collected and imaged.

This increases the contrast and sensiti-vity of the system, enabling it to detectvery small defects.


The top illustration shows the dark-field image of a cluster of spherical na-noparticles made of polystyrene latex,with a diameter of 112 nm, on a filmof silicon nitride with a thickness of150 nm, taken using the EUV transmis-sion microscope at the Fraunhofer ILTin cooperation with the Chair of OpticalSystems Technologies TOS at RWTHAachen. A defect scan at 0.1 mJ/cm2

on the surface (single-pulse mode) wassuccessfully demonstrated. The scann-ing rate is limited by the readout timeand the size of the CCD. If transferredto applications such as mask-blank orwafer inspection, this corresponds to amaximum scanning rate of 3 cm2/hour.

When the system is used to measureparticles, it is possible to derive the in-tensity of the scattered light from theknown variables: detector sensitivity,intensity of the incident light, and thetransmission of the optical system.Comparing this result with calculationsperformed using the Mie theory, whichprovides an exact description of thelight scattered by spherical particles,enables not only the size but also therefractive index (and hence the mate-rial) of the light-scattering particles tobe determined.

Contact

Dr. L. Juschkin, Tel.: [email protected]. W. Neff, Tel.: [email protected]. Dr. P. Loosen, Tel.: [email protected]


EUV microscopy for defect inspection on surfaces and thin films

60 x 80 Pixels

Above: Dark-field image of a cluster of spherical nano-particles at 13.5 nm.Middle: Line scan along thewhite line in the image above.Below: EUV transmission mi-croscope at the Fraunhofer ILT.

λ =13.5 nm

Number of pixels

Inte

nsi

ty,c

ts

Task

Compact, easy-to-operate devices formonitoring extreme ultraviolet radiationare indispensable to the developmentof beam sources operating in this re-gion of the spectrum. The activity ofgreatest interest today, that of deve-loping sources for extreme ultravioletlithography, calls for energy detectorscapable of monitoring the photon flowwithin a limited spectral bandwidth of 2% or 0.27 nm with a center wave-length of 13.5 nm.

Method

An energy monitor of the described type was built and tested as part of the Fraunhofer ILT’s joint developmentwork on high-power sources for EUVlithography, conducted in partnershipwith Philips. The monitor is based onan off-the-shelf photodiode coatedwith a material that filters out wave-lengths above the extreme ultravioletrange. The diode is connected to aspectral filter consisting of two multi-layer mirrors, which have the necessarybandwidth of 2% and are thus ideallysuited for simulating the spectral trans-mission characteristic of optical systemsused in EUV lithography. The signalemitted by the diode can be read outdirectly on an oscilloscope connectedto the monitor by a BNC cable.

The energy monitors are calibrated atthe Fraunhofer ILT with reference to aknown standard whose characteristicshave been defined by a recognizedmetrology institute such as the Physi-kalisch-Technische Bundesanstalt (PTB)in Berlin. Calibration is performedusing a compact pulsed source to whichboth energy monitors are connected at

the same time and at the same relativeangle to the beam source. The repro-ducibility of the results is better than 1%.

Because the reflectivity of the multilayermirror varies as a function of the angleof incidence, it must be ensured thatthe optical axis of the energy monitoris perfectly aligned with the beamsource. Repeated measurements of theemission spectra of tin and xenon re-vealed that an angular misalignment of approximately 1 degree could be regarded as the tolerance limit whenaiming to achieve an accuracy of betterthan 2%, which as a general rule is automatically ensured by the mechani-cal design of the vacuum system.


The energy monitor has a length of 22 cm and is connected to the source’svacuum system by means of a CF40flange. A center wavelength of 13.5nm is produced at a spectral band-width of 0.27 nm. The signals are readout via a 50 Ω oscilloscope input. Theminimum pulse duration is determinedby the diode and lies in the region of 2 µs. The typical signal amplitude is 30 mV/(mJ sr) when the monitor is placed at a distance of 70 cm from the source.

Contact

Dr. K. Bergmann, Tel.: [email protected]. W. Neff, Tel.: [email protected]


Energy monitor for extreme ultraviolet radiation

Energy monitor for emissions inthe region of 13.5 nm.

Task

Extreme ultraviolet (EUV) radiation isgenerated with a vacuum arc ignitedby laser-induced ablation of the cathodesurface. The radiant power of the lasercreates a plasma, which propagates tothe anode. When the plasma touchesthe surface of the anode, electricaldischarge begins. This heats the plas-ma to the point of emitting EUV radia-tion. As well as being dependent onthe laser parameters, the radiationcharacteristic is determined by the current distribution in the plasma. The plasma variables and the currentdensity are calculated.

Method

Maxwell equations were implementedfor the two-dimensional plasma modeldeveloped the year before. A cathodedrop model was produced for the transition between the plasma and thecathode and integrated in the plasmamodel. The new model can be used tocalculate the electromagnetic variablesas a function of time and space, in ad-dition to the plasma variables.


The electron density, current densityand velocity field were calculated for the instant of maximum current(approx. 12 kA). The greatest electrondensity is found at the surface of thecathode (0) (top image left).

As a result of the pressure gradient,the plasma velocity increases towardsthe anode. The Lorentz force inhibitsradial expansion, obliging the distribu-tion to spread chiefly along the axis ofsymmetry (0-d). At the anode (d), the

Lorentz force accelerates the plasmatowards the axis of symmetry and thecathode (middle image left). The twoopposing flows form a stagnant zoneon the axis of symmetry containing adensity maximum (top image left). Thecurrent distribution exhibits its highestvalues at the surface of cathode andanode respectively (bottom image left).The zone producing the highest EUVemissions corresponds to the zonewith the highest electron density,which is found in the vicinity of thecathode. This result has been validatedexperimentally.

Contact

Dr. M. Aden, Tel.: [email protected]. Dr. W. Schulz, Tel.: [email protected]


Simulation of laser-induced vacuum discharge

Above: Electron density at the instant of maximum currentbetween cathode (0) and anode (d).Middle: Velocity field at the instant of maximum current.Below: Current density at theinstant of maximum current.

Laser Material Processing

Production processes addressed by this business area include cutting andjoining techniques applying micro- andmacro-technology, as well as surfaceengineering. The services provided extend from process development forthe manufacture of sector-specific products and the integration of theseprocesses in production lines, throughsimulation services for laser applications,to the production of samples in sup-port of series production start-up. Thestrength of the business area is rootedin its extensive process know-how,which is tailored to specific customerrequirements in each case. In additionto process development, the businessarea offers complete system solutionswhich utilize selected technology net-works. Customers are offered laser-specific solutions that encompass designengineering, material specification,product design, production equipmentand quality assurance. In addition tothe target market of material process-ing, the business area also addressescustomers in the medical engineering,biotechnology and chemical sectors.


Business AreaLaser Material Processing

Mold cores of an injection molding tool. Left: Blank, right: Finish-machined part.

High-speed cutting with fiber lasers 62

Remote cutting of sheet metal 63

Welding of electric contacts for high peak currents 64

CO2 laser MAG hybrid welding for wall thicknesses up to 30 mm 65

High-speed welding of steels using fiber lasers 66

Integrated production of tailoredblanks using the combi-head 67

Combi processing with fiber diameters of 50 and 600 µm 68

Laser post-treatment of ceramic coatings 69

Surface melting of a single-crystal solidified nickel alloy for gas turbinecomponents 70

Polishing of titanium by pulsed laser 71

Analysis of the flow-off behavior during laser cleaning 72

Process simulation for laser-beam structuring 73

Graduated materials yield improved characteristics 74

Micro-laser-beam deposition welding 75

Generative production of microcoolers 76

Manufacturing of ceramic components by selective laser melting 77

Computational steering system for parallelized simulation calculations 78

Process control in microwelding 79

Detection of process faults in micro-spot-welding 80

Development of a miniaturized scanner system for laser-beam microjoining 81

Microwelding of plastics by fiber laser 82

Laser welding of thermoplastics without the addition of absorbers 83

Beam widening during laser welding of plastics: Determining the scattering coefficient of PA 66 84

Laser-assisted selective bonding of similar and dissimilar classes of brittle hard material 85

Colored markings in glass 86

Product labeling with the aid of nanostructures 87

Manufacturing of waveguide lasers by pulsed laser deposition and fs-laser microstructuring 88

Sub-wavelength ripples: Forming periodic nanostructures by fs-laser radiation 89

Laser-assisted punching 90

Laser-based solar cell technology 91

Drill holes with a high aspect ratio 92

Drilling and cutting of contoured holes 93

Offline determination of workpiece-penetration during percussion drilling 94

Efficient expulsion of melt during laser percussion drilling 95

Effective ray tracing for multiple reflections during laser cutting and drilling 96

High-speed microdrilling of transparent metal foils 97

Microdrilling of holes in pharmaceutical packaging for the validation of test equipment 98

Laser-diode-assisted transformation of plant cells 99

Temporally resolved quantitative phase microscopy 100



Überschrift

Contents

Task

Up to an output of 4 kW (as at the end of 2006), the beam quality of fiberlasers is significantly higher than thebest beam quality theoretically possiblefor CO2 lasers. This means that, takenin conjunction with the better absorp-tion of solid-state lasers over a widerange of parameters, fiber lasers canachieve considerably better process efficiencies than CO2 lasers. In terms of cutting processes, this is particularlyuseful for handling thin sheet metals.The maximum speeds for different out-puts were determined, using mild steelof 1 mm thickness as an example.

Method

The cutting tests were carried outusing a fiber laser with a maximum laser beam output of 4 kW and a fiberdiameter of 50 µm. The beam para-meter product was 1.8 mm mrad.

The focusing dimensions and the sett-ings for all other process parameterswere adjusted to match the low thick-ness of the metal sheet.

To make it possible to classify the ex-perimental results, the probable maxi-mum speed was calculated at the sametime, using the CALCut simulation program.


We succeeded in producing cuts withan excellent edge quality at extremelyhigh cutting speeds (v = 135 m/min @ 4 kW, Rz = 6.6 µm). The numericalsimulations and the experimental results were highly concordant. The simulation also shows that the maxi-mum speeds attained are not far shortof the theoretical limit that can be reached using diffraction-limited laserswith a corresponding power output.

Speeds as high as these are of particu-lar interest for linear applications suchas trimming or longitudinal and lateralsplitting of strip material. Even profil-ing facilities with very high accelerationrates can only realize these speedswhen the contours are large enough.For 2-D and 3-D applications using lowerspeeds, the installed laser power canbe reduced accordingly. Among theapplications that benefit from thesedevelopments is the cutting and trimm-ing of deep-drawn components, par-ticularly those made of high-strengthmaterials that are difficult to handle in mechanical cutting. Together withthe excellent process efficiency of fiberlasers (approx. 25%), the method offerspotential savings in terms of both invest-ment and operating costs.

Contact

Dr. F. Schneider, Tel.: [email protected]. D. Petring, Tel.: [email protected]


High-speed cutting with fiber lasers

Cut edge of 1 mm mild steel, cut at 135 m/min (Rz = 6,6 µm,burr-free).

Task

The outstanding brilliance of modernfiber and disc lasers has the potentialfor developing processes which havenot been able to be implemented untilnow. The task was to examine whetherthe advantages of remote processingwith scanners can also be used for cutting metals.

Method

Experiments were performed using a fiber laser connected to a scanner. Theuseful power was limited to 1.5 kWdue to restrictions of the used scanner.The tests were carried out on thinstainless steel sheets with thicknesses ≤0.5 mm.


The selected system configuration provides demonstrable proof of thefeasibility of the remote cutting of metals.

In the present case, as in conventionalcutting techniques, most of the materialin the cut gap is ablated in its moltenform. The physical process used todrive the melt out of the cut gap, evenwithout the driving force of a gas jet, is the vapor pressure gradient in the interaction zone. Since this effect ispromoted with increasing intensity, it is particularly important that the laserbeams employed should be well fo-cusable. Recent progress in the outputand beam quality of solid-state lasersoffers promising prospects for the re-mote technique.

If this method is further optimized anddeveloped to industrial maturity, theuse of the scanner and the ability todispense with the cutting head willproduce practical benefits due to thesimpler machining setup and the shorterprocessing times that is possible toachieve as a result of the more dynamicprocess. It will thus be possible to reachhigh cutting speeds even in small radii,and the times between the cuttingoperations will be virtually negligible.

Contact



Remote cutting of sheet metal

Above: Remote cutting of steels.Below: Edge produced by remote cutting.

Task

In the field of industrial electronics,new ways of welding electric contactsmore cheaply and efficiently are beingsought.

In future, resistance welding will be replaced by laser beam welding as a means of joining tin-plated con-ductors. In contrast to the resistancewelding method, laser welding is distortion-free and has a shorter cycletime. There is no need for parts to bepressed together from two sides tocreate a welded joint; it is sufficient for the seam to be accessible from oneside.

The welded seam must be capable of withstanding high peak currents of several multiples of 10 kA and a mechanical shearing force of at least400 N.

Method

In the context of a feasibility study, theprocess parameters were set in such away that a full penetration weld of theseam with a joining width ≥ 0.8 mmwas achieved with a laser output ofapprox. 3 kW.

The welds were produced using a fiberlaser of high beam quality (1.8 mmmrad, maximum output 4 kW, fiberdiameter 50 µm). The materials weldedwere copper alloys with a materialthickness of 1.5 mm and 0.8 mm inthe lap joint.


With a welding time of 0.045 sec for each contact, an adhesion width of more than 0.8 mm at the joiningsection and a full penetration weld ofthe seam, the specified requirementsfor the welding process were fulfilled.

Laser welding of copper materialsholds attractive potential for develop-ing sophisticated joining techniques for use in such fields as high-powerelectronics, cooling technology and solar thermal applications.

Contact

V. Nazery Goneghany, Tel.: [email protected]. D. Petring, Tel.: [email protected]


Welding of electric contacts for high peak currents

Cross-section through a weld in tin-plated copper at the lapjoint.

Task

In the shipbuilding industry, CO2 laserMAG hybrid welding is a firmly estab-lished technique for metal plates withwall thicknesses up to 15 mm. How-ever, there is a great need to further refine the technique so that it can alsobe used for wall thicknesses up to 30 mm. The goal of HYBLAS, a currentEuropean project funded by the RFCS,is to develop process procedures for laser hybrid welding of structural andfine-grained structural steels with yieldstrengths of up to 690 MPa and wallthicknesses up to 30 mm.

Method

A Trumpf TLF 20000t CO2 laser and aFronius TPS450 programmable weldingpower source were used for the tests.The test welds were performed in thePA, PB and PC weld positions. To op-timize the results, not only the laserparameters and the wire feed, but alsoa variety of weld preparations such asV, Y, HY and DY welds with differentincluded angles were examined. Thewelds were performed on butt, T andcorner joints.


For material thicknesses in the 15-25mm range, wide process windows interms of the laser output and the gapwere developed for MAG process con-figurations with leading or trailing wirefeed, enabling high-quality welds to be performed. Using optimized para-meters, we achieved results such asthe ability to bridge gaps of up to 3 mm in a wall thickness of 15 mm. In addition to the usual samples formechanical and technological investi-

gations, large samples measuring2,000 mm x 500 mm were prepared.Besides plate material, we also produceddemonstrators such as joints of pipesto plate flanges. Fine-grained structuralsteel of 30 mm thickness was laser hybrid welded with satisfactory results,welding from both sides simultaneous-ly with two MAG power sources. Inthe thickness range up to 25 mm, wewere able to produce welds withoutany hot cracks compliant with the highest assessment group B of EN ISO13919-1.

The advantages of laser MAG hybridwelding are its high welding speed,low distortion, ability to bridge gaps,and the capability of single-pass weld-ing. Applications for these wall thick-nesses can be found in pipeline con-struction, shipbuilding, load-bearingstructures, off-shore engineering, spe-cial constructions and in heavy vehicleconstruction.

The work is being performed as part ofthe EU project »Economical and safelaser hybrid welding of structural steel- HYBLAS«, which is sponsored by theResearch Fund for Coal and Steel.

Contact

Dipl.-Ing. N. Wolf, Tel.: [email protected]. D. Petring, Tel.: [email protected]


CO2 laser MAG hybrid welding for wall thicknessesup to 30 mm

Above: 25 mm laser-MAG hybrid weld, butt joint, vs = 0,6m/min, PL = 14.1 kW, PC position.Below: Demonstrator compo-nent.

Task

For a steel material with a sheet thick-ness of up to 3 mm, the maximum feedrates at which welding is possible with-out humping are to be determined.»Humping« is a term used to refer to adynamic process in the weld pool thatoccurs particularly at high weldingspeeds, causing unwanted humps anddeficiencies to form at periodic intervalsalong the weld. By varying the parame-ters, it is hoped to push the humpingthreshold to speeds as high as possible.

Method

A 4 kW fiber laser with a fiber diameterof 50 µm was used for the tests. Thesheet thickness, the laser output andthe welding speed were varied withina certain experimental matrix in orderto determine the weld penetration limits and the threshold below whichthe process can be performed withouthumping.

The high beam quality helps to complywith the requirement for narrow welds.


In the welding of thin metal sheets, as in other materials processing tech-niques, it can be observed that thehigh beam quality of fiber lasers per-mits a significant increase in the pro-cessing speed. The speed at which the weld penetration limit is reached is considerably higher than in compa-rable test results using a CO2 laser. By adjusting the laser beam output, itproved possible to raise the thresholdat which the humping effect occurs tospeeds of up to 40 m/min (sheet thick-ness 0.6 mm), an important considera-tion for the customer. The welding results were excellent.

Optimizing measures, such as speciallyshaping or directing the beam, werenot used in this experiment and will infuture produce even higher boundaryspeeds that are of great interest to industry, particularly for use on long, linear welds.

Contact



High-speed welding of steels using fiber lasers

Weld cross-section at a weldingspeed of 18 m/min below thehumping threshold (sheet thick-ness 1.6 mm, laser beam output2 kW).

Task

Particularly in the production of non-linear tailored blanks, lack of precisioncauses gaps to form between the edgesbeing joined. This makes it all the moreimportant to trace the weld accurately.Integrated cutting and welding with thecombi-head opens up new possibilitiesin this context.

The combi-head is software-controlledand can switch rapidly between the la-ser-beam cutting and welding processeswithout any need to adjust the tool it-self.

Method

Demonstration blanks with small di-mensions are prepared with the aid ofan off-the-shelf combi-head based onthe Fraunhofer ILT demonstrator. Inte-grated focusing optics and a z-axis fordistance control enable it to meet thedemands of industrial operation. A fiberlaser with a process fiber diameter of100 µm is employed as the beam source.

The joining edges of the two blanks arefirst prepared with two laser cuts, thenimmediately welded along the identicalpath within the same clamping device.To conclude the process, two elongatedholes positioned exactly to one anotherare cut out.

The blanks are made from two differ-ently galvanized car body materials withthicknesses of 1.0 and 1.2 mm.


The integrated manufacturing processwas demonstrated to produce non-linear cuts and welds of very high quality.It is particularly worth noting that thewelding line can be located without aweld tracking system because the preciseposition of the weld is known to themachine coordinate system from the laser cut that precedes it.

After welding, drill-holes, contoured cutouts or edge cuts can be performedon the metal sheets while clamped inthe same position. This option furtherenhances manufacturing flexibility andthe number of different variations thatcan economically be produced. Thesesubsequent cutouts can even be madeacross the weld itself, resulting in ahigh-precision component.

The integrated production of tailoredblanks is an attractive alternative in themanufacture of small and mid-sizedbatches in view of the fact that signi-ficant progress has been achieved, particularly in terms of the processingspeeds for cutting thin metal sheets,not least as a result of the meanwhileexcellent beam quality of CO2 and solid-state lasers.

Contact



Integrated production of tailored blanks using the combi-head

Cutting of joining edges followed immediately by welding.

Task

Materials processing with solid-statelasers can be subject to distinctly diffe-rent focusing conditions, dependingon the beam source employed. Forexample, the beam quality of lamp-pumped rod lasers with a fiber diame-ter of 600 µm, which are still extremelywidespread, is inferior by a factor ofmore than 10 to that of state-of-the-art fiber lasers with a fiber diameter of 50 µm. A comparative investigationwas performed to find out what effectthe use of such widely varying fiberdiameters has on combi processing inparticular.

Method

Meaningful system and process para-meters were defined for the purposesof the comparison and had to be ob-served in all tests using the two fiberdiameters of 50 and 600 µm. They included Rayleigh length ≥ 2 mm, Fnumber ≥ 5, laser beam output 4 kW,nozzle spacing for cutting 1 mm, nozzle spacing for welding ≥ 6 mm,working distance for optics ≥ 200 mm,processing speed 5 m/min.

The process windows for the focus position and nozzle spacing are smallerfor cutting than for welding. The sett-ings used for cutting are therefore taken as a starting point for deter-mining the scope available for weldingin terms of weld penetration and shaping at different nozzle distances.


Just as in specialized cutting and weld-ing applications, it was found that high welding and cutting speeds, insome cases up to a factor of 2 higherthan the standard values so far, can also be achieved in combi processingusing the small fiber diameter of 50 µmand the good beam quality associatedwith it. In other words, narrow weldswith a high depth of penetration canbe produced.

However, combi processing particularlybenefits from the narrow caustic thatcan be produced with the 50 µm fiberbecause the window within which thedesired weld shape and penetrationcan be adjusted by defocusing is sig-nificantly larger than when using a lesser beam quality. The nozzle spacingduring welding, which may thus varywithin a correspondingly wide range,has very little influence on the process.

The experiments revealed viable para-meter windows for combi processingalso with lamp-pumped lasers. How-ever, greater flexibility and a broaderspectrum of applications in terms of speed, quality, ways of shaping the weld, etc., can be achieved whenusing more modern beam sources suchas fiber or disk lasers.

Contact



Combi processing with fiber diameters of 50 and 600 µm

Spatial distribution of the isophots at the focus of a fiberlaser (left) and of a conventionalNd:YAG laser (right) under thefocusing conditions defined bythe process parameters.

Task

Thermal spray ceramic coatings haveexcellent wear-resistance properties. Incorrosive environments, however, theycan only be used to a limited extentowing to their residual porosity (upperfigure). This project sets out to increasethe corrosion-resistance of ceramiccoatings by laser surface melting of a Cr3C2-NiCr coating. A recurring problem in the laser treatment of theCr3C2-NiCr coating is the formation of cracks due to the high brittleness ofceramic materials.

Method

The process parameters were deter-mined using flat samples made of du-plex steel. The thickness of the duplexsteel substrate was 5 mm and thethickness of the Cr3C2-NiCr film was70 µm to 90 µm. A Nd:YAG laser with a beam diameter of 400 µm was em-ployed. The preheating temperature,the laser output power, the feed rateand the trace offset were varied.


The Cr3C2-NiCr coating was surface-melted to a melt depth of up to 20 µmwhen processed at room temperature.However, it was not possible to pre-vent the formation of cracks in themelted surface layer, no matter whichparameters were used.

The lower figure shows a cross-sectionof a Cr3C2-NiCr coating after lasertreatment. A crack-free surface layerwas achieved by carefully selecting theprocess parameters especially the pre-heating temperature so as to reducethermal stress. The melt depth was 25 µm.

One potentially interesting industrialapplication of thermal sprayed Cr3C2-NiCr coatings would be for thefunctional surfaces of high-pressurepumps for seawater desalination.

Contact

Dipl.-Ing. D. Maischner, Tel.: [email protected]. K. Wissenbach, Tel.: -147 [email protected]


Laser post-treatment of ceramic coatings

Above: SEM image of the surface of an untreated Cr3C2-NiCr coating.Below: OM image of the cross-section of a Cr3C2-NiCrcoating after laser treatment.

10 µm

100 µm

Task

The aim of the investigation is to de-velop a remelting process for repairingdamaged areas of single-crystal solidi-fied alloy turbine blades with a single-crystal solidified material. Cracks in theplatform, the radius or the blade of the gas turbine blade are removed byremelting whilst retaining the single-crystal structure. The remelted areasmust be free of pores and cracks, andexhibit homogenous dendritic growthalong the whole length of the layer.

Method

First of all, a suitable set of equipmentwith a laser beam source, optics andhandling system is prepared. The sup-ply of inert gas to prevent oxidation re-presents a special challenge. To protectthe surface from oxidation, the flat testpieces are remelted in a processingchamber flooded with the inert gas argon. In the first step, the remelt pro-perties - remelt depth, remelt widthand dendritic growth - are examinedas a function of the process parame-ters, e.g. laser output power, beamgeometry and feed rate, in order todetermine the most suitable parame-ters. The laser remelting process is per-formed on flat test pieces.


The selection of suitable process para-meters enabled a remelt zone with asingle-crystal structure to be produced.Subsequently, an area of the surfacewas remelted using an overlappingstrategy. A further positive outcome of the project was the implementationof a special process control systemwhich made it possible to achieve a remelt of a depth relevant to turbineblade repairs.

On the basis of these results, laser surface melting is to be tested on othersample geometries and on whole turbine blades.

Contact

Dipl.-Ing. Bernd Burbaum, Tel.: [email protected]. Torsten Jambor, Tel.: [email protected]. Konrad Wissenbach, Tel.: [email protected]


Surface melting of a single-crystal solidified nickel alloy for gas turbine components

Above: Cross-section of a melted track with a single-crystal structure.Below: Cross-section of twooverlapping tracks with a single-crystal structure.

1000 µm

2000 µm

Task

The polishing of titanium and titaniumalloys such as TiAl6V4 is a work-inten-sive process when using conventionalmachining techniques, because thematerial tends to 'smear' under con-tact with mechanical tools. As part of aproject called 'LaserFinish', researchersare investigating the use of a pulsed la-ser to polish titanium parts. Such partsare intended for applications in humanmedicine, in the fabrication of blood-conducting implants. The main require-ments for the surface of these compo-nents are that it should:• reduce the friction between blood

constituents and the surface, to minimize or prevent damage to the blood.

• prevent blood constituents from adhering to the surface, to prevent thrombosis.

Method

By performing tests on flat samples,the researchers established suitableprocess parameters for laser-polishingof the titanium material TiAl6V4. Pro-cessing strategies were developed forpolishing complete three-dimensionalparts, and their geometry was pro-grammed. The surfaces were analyzedby means of white-light interferometry,light microscopy and scanning electronmicroscopy. Functional testing of theparts is being carried out by the projectpartner.


The roughness of milled titanium sur-faces can currently be reduced from Ra = 0.25 µm to Ra = 0.08 µm. Theprocessing time in this case is of 3.3s/cm2.

Conventional grinding and polishingprocesses can result in scoring, andsubsequent grinding steps can produce'smeared-over' surface defects. Rem-nants of the grinding agent, bacteriaand other impurities can then cling tothese defective areas. During laser po-lishing, the surface solidifies from themolten state. Sharp-edged scratches,smeared-over grinding ridges and un-dercuts do not occur. When examinedunder a microscope, the surface is thusfree of defects and offers a high levelof biocompatibility.

Divided into 11 subareas, the entiregeometry of a titanium part was po-lished in 2 minutes. No borders are visiblebetween the consecutively polishedsubareas, for example between thewing and the cylinder. The next step isfor the project partner to characterizethe properties of the laser-polished surfaces and finished parts in greaterdetail.

Contact

Dipl.-Ing. S. Hack, Tel.: [email protected]. E. Willenborg, Tel.: [email protected]. K. Wissenbach, Tel.: [email protected]


Polishing of titanium by pulsed laser

Above: Titanium implants,right: initial state, left: polishedwith a laser.Middle: Initial state, milled.Below: Polished with a laser.

50 µm

50 µm

Task

Laser cleaning is an ablative processwhich generates ablated products inthe form of gases and particles. It isimportant that these ablated productsare collected thoroughly by means of an adapted suction technique to ensure high process efficiency, a high surface cleanliness, compliance withworkplace health and safety regula-tions, and adequate protection of thelaser optics against soiling. To achievehigh ablation rates, the tendency is touse increased laser outputs (> 500 W), particularly when cleaning with Q-switched Nd:YAG lasers. This intensifiesthe problem of collecting the ablatedproducts, as these accumulate in in-creasingly large amounts per given timeperiod. The goal is thus to developsuitable methods of analyzing theflow-off behavior of the material duringlaser cleaning, such that the collectionrate may be increased by means of asuitable suction technique and withthe help of optimized nozzle geome-tries and arrangements.

Method

In order to analyze the highly dynamicflow-off processes taking place, the re-searchers set-up a visualization systembased on a high-speed video camera(4,500 frames/s). The illumination andfilter systems employed must fulfillspecial requirements in order to filterout light emitted by the process. A diodelaser combined with a band-pass filterhas proven to be a suitable option. Thelaser beam is shaped in such a waythat a kind of 'light section' is genera-ted in the observation plane, allowingthe flow-off behavior to be monitored

in a single plane with a depth of approx.1 mm. By analyzing individual framesand image sequences, quantitativeconclusions can be drawn regardingthe main flow-off direction as well asthe speed and direction of individualparticles under various test conditions.


Without suction (top image left), thedominant flow-off direction is almostperpendicular to the surface. The laserlight interacts with the ablated pro-ducts over a considerable distance, resulting in poor process efficiency. The particles reach a velocity of up to90 m/s. By finding a more suitable po-sition for the suction nozzle relative tothe incident laser light (bottom imageleft), this interaction is reduced and theablated products are almost fully collec-ted. This not only helps to improveprocess efficiency but also to preventthe lens system from becoming soiled.

The next step is to automate the extremely time-consuming manualanalysis of the image sequences.

Contact

Dipl.-Phys. C. Johnigk, Tel.: [email protected]. K. Wissenbach, Tel.: [email protected]


Analysis of the flow-off behavior during laser cleaning

Above: Free flow-off withoutsuction.Below: Ablation process withsuitably positioned suctionnozzle.

Task

In addition to structure and chemicalcomposition, the topography of a sur-face has a significant bearing on itsfunctional properties.

A completely new technique for thestructuring of surfaces is that of laser-beam remelting. By combining thistechnique with the laser polishing me-thod developed at the Fraunhofer ILT,which is also a remelting process, it ispossible to achieve significant synergyeffects, as surfaces can be simulta-neously polished and structured in asingle process step (figure top left).

The surface is structured by redistri-buting the material in its molten state.The topography obtained results fromthe kinematics of the three-phase line,which can be influenced, for example,by modulating the laser output power.In mathematical terms, surface meltingwith laser radiation can be representedas a free boundary value problem. Anin-depth understanding of the processis being developed on the basis of aself-consistent numerical solution, inorder to derive the information requi-red to improve process layout.

Method

A solution to the free boundary valueproblem comprises the self-consistentreciprocally coupled calculation of tem-perature distribution and Marangoniflow, and the dynamic of the free phase transformation interface and the melt surface, which is importantfor surface topography formation.

For this purpose, a model was createdwhich takes into account the pressurebalance equation for calculating thegeometry of the melt surface, a balanceequation for the melt volume and thecoupling between deformation of themelt surface and the kinematics of thethree-phase line along the solidificationfront.


The comparison with experimental results for single tracks shows a goodconcordance with regard to the result-ing surface topography (figure bottomleft). The surface structure was producedby harmonically modulating the laseroutput power. The model will be usedto determine the cause-and-effect re-lationship between the process para-meters and the resulting surface topo-graphy, and will thus help to establishthe process limits, initially for singletracks. In addition, the model will beexpanded in order to calculate whichkind of surface structures can be gene-rated by overlap processing of singletracks.

Contact

Dr. N. Pirch, Tel.: [email protected]. K. Wissenbach, Tel.: [email protected]


Process simulation for laser-beam structuring

Above: Topography of a steelsurface (15 * 15 mm2) structuredand polished with a laser.Below: Comparison of the surface topography of a singletrack, experimental (above) and calculated (below), in a 3-D isopleth diagram

Task

The manufacturers of injection-moldingand die-casting tools are seeking todevelop products which will meet in-creasingly complex requirements andprovide improved functional properties.In many cases these aims cannot beachieved with a single, homogeneousmaterial. A solution to this problem is offered by graduated materials inwhich various properties, such as corrosion and wear resistance ortoughness and strength, are combinedthrough variation of the chemical com-position.

The objective is to harmonize the pro-perties in such a way that tool life is increased and cycle times for the pro-duction of plastic or aluminum compo-nents are reduced.

Method

Two different approaches are beingpursued for the manufacture of gradient layers:• Laser-beam deposition welding

of gradient layers on a blank.• Laser-beam generation of complete

tool inserts which have a graduated structure.


Injection mold cores have to quicklyconduct the heat away from the plasticin order to keep the cycle time downand to ensure good demoldability.Copper fulfills the requirements in thisrespect but its resistance to wear andcorrosion is inadequate for most ap-plications. The top figure shows theblank and a finish-machined mold corewhich has been coated with a gradua-ted layer on a steel basis. Field testsshow that this mold core cools morequickly after the injection operationcompared with mold cores made oftool steel, and as a result demoldabilityis improved. The gradient coating en-sures wear resistance on a par withtool steel. The bottom figure shows agraduated tool insert for a die-castingmold, produced by a means of lasergeneration. The core is made of toughstainless steel and the enclosure con-sists of a wear- and corrosion-resistantsteel alloy. The aim is to reduce the risk of heat cracking by combiningtoughness and strength in the volumeof the mold. The tool inserts are cur-rently being tested.

Contact

Dr. A. Weisheit, Tel.: [email protected]. K. Wissenbach, Tel.: [email protected]


Graduated materials yield improved characteristics

Above: Mold cores of an injection molding tool.Left: Blank, right: Finish-machined part.Below: Laser-generated tool insert.

15 mm

20 mm

Task

Process techniques are being developedfor laser-beam deposition weldingusing powder filler material which willmake it possible to produce structuresizes of < 100 µm. With precise ma-terial deposition, the surfaces of micro-components will be repaired by depo-sition of similar material or selectivelymodified (coating, dispersion) by de-position of dissimilar material. With selected parameters 2-D and 3-Dfunctional surfaces are being producedon components from the tool and die,electrical and medical device sectors.The repaired or modified surfaces are being tested and assessed by theproject partners in respect of their pro-cessability and functional properties.

Method

To achieve the required structural sizes,continuous-wave fiber lasers and pulsed Nd:YAG lasers are used. Thepowder gas system is being further developed to deliver filler powderswith grain fractions of < 20 µm. Theaim is to increase the efficiency of thepowder inflow by adapting existingcoaxial nozzles. The impact of the pro-cess parameters including laser power,beam diameter, feed rate, powdermass flow and powder particle size onthe welding result is being examined inexperimental investigations.

Fundamental studies are being con-ducted with the filler materials 1.2343and 316L on steel. In parallel, para-meter windows for nickel-based andcobalt-based alloys, titanium, gold andsilver are being determined.


Powder-focus diameters of < 200 µmcan be achieved using the adaptedcoaxial nozzle, which improves thepowder inflow efficiency comparedwith conventional powder infeed nozzles by a factor of 2. By using metal powders with particle diametersof < 20 µm, structure resolution can berefined by a factor of 3 to 5 comparedwith the state of the art. By way ofexample, the top picture shows a singletrack of 316L with a track width ofabout 45 µm and a track height of 10 µm. Surface coatings can be pro-duced by juxtaposing single tracks(middle and bottom figures). Thecoating consists of 20 individual tracksand has a coating height of 10 µm.

Contact

Dipl.-Ing. T. Jambor, Tel.: [email protected]. K. Wissenbach, Tel.: [email protected]


Micro-laser-beam deposition welding

50 µm

Above: Micrograph of a singletrack of 316L on stainless steel.Middle: Micrograph of acoating created by 20 individualtracks of 316L on stainless steel.Below: Surface topography of acoating created by 20 individualtracks of 316L on stainless steel.

100 µm

Task

Diode laser bars are actively cooled to remove the heat generated in laseroperation. The microchannel heat sinksused for this purpose are made of copper and feature an internal water-conducting microstructure. Unfortu-nately, the service life of the diode laserbars is often shortened because theheat sinks become corroded. For thisreason, microchannel heat sinks madeof corrosion-resistant material are re-quired. One approach in pursuit of thisobjective is to generatively producethem from a corrosion-resistant nickelalloy by means of Selective Laser Melt-ing (SLM). The aim is to make up forthe lower thermal conductivity of theNi material compared with copper bycreating an inner microstructure whichis more effective in terms of heattransfer. This requires the developmentof a SLM process to produce structuresizes of approx. 100 µm.

Method

In SLM the size of the structure thatcan be produced is determined by thediameter of the focused laser beam.Up to now, a diode-pumped solid-statelaser with a beam diameter in the fo-cus of 200 µm has been used for theSLM process. A fiber laser is now beingused to create microstructures. Thanksto the higher beam quality it is possi-ble to achieve a beam diameter in thefocus of 70 µm while retaining the same optical conditions. The SLM pro-cess parameters are adapted to the re-duced beam diameter in such a waythat the components produced exhibita density of approx. 100 %. In addition,a suitable scanning strategy is beingdeveloped for the production of micro-structures.


By reducing the beam diameter andadapting the process accordingly, thesmallest structure size (rib width) ofapprox. 300 µm which can be producedusing SLM can be reduced to approx.100 µm, which is adequate for creatingthe inner microstructure for the micro-channel heat sink. This means thatSLM can be used to produce micro-channel heat sinks with outer dimen-sions of 1.2 mm x 12 mm x 26 mmand an internal microstructure con-sisting of water-conducting channelswith a width of 250 µm / 150 µm andribs between the channels of 100 µm.The powder remaining inside the mi-crostructure on completion of the pro-cess can be removed without difficultyusing compressed air. Depending on the geometry of the inner micro-structure, the water throughflow ratereaches 1.2 l/min at a pressure of 1.5 bar. The SLM system can produceapprox. 50 microchannel heat sinkswith the above dimensions simulta-neously.

Contact

Dr. W. Meiners, Tel.: [email protected] Dr. K. Wissenbach, Tel.: [email protected]


Generative production of microcoolers

SEM image showing the micro-structure of a microchannel heat sink produced using SLM.

1 mm

Task

The generative process of selective laser melting makes it possible to produce complex three-dimensionalcomponents very quickly layer by layerfrom a powder starting material. Thisprocess is already used in industry to make many series-produced com-ponents from metallic materials.

At the Fraunhofer ILT, work is beingconducted on the further developmentof selective laser melting for processingceramic materials. The aim is to deve-lop a process by which componentsmade of high-strength oxide ceramiccan be produced generatively withgreat accuracy.

Method

Various approaches are being pursued,including direct melting of ceramicpowder, a reaction-sintering methodand a technique in which a compositeceramic and glass material is processedby laser melting. The first approachmentioned, which focuses on the complete melting of purely ceramicpowder, is delivering promising results.By using flexibly modified test facilitiesin combination with various laser-beamsources, the technology is being adap-ted to the specific requirements of ce-ramic materials.


Using a zircon oxide (ZrO2)-based ma-terial, a very high component densityof over 98%, i.e. an almost pore-freestructure, is attained. The demonstrationcomponents illustrated here exhibit an accuracy of better than ± 0.2 mmand a good surface finish (Rz < 60 µm).In principle, spinel (MgAl2O4) and aluminum oxide (Al2O3) can also beprocessed by laser melting. On all the materials used up to now, however, fine structural cracks can be observedwhich limit the material’s strength.One way of solving this crack problemis to preheat the basic platform and toheat the component during the entireprocess in order to reduce thermally in-duced stresses. Preheating temperaturesof up to 900 °C have already beenachieved and a device which will pro-duce distinctly higher temperatures iscurrently being developed. The subse-quent glass infiltration of the ceramicbodies produced is also being examinedas an alternative.

One potential application is e.g. theproduction of shell moulds for precisioncasting. As soon as an adequatestrength can be attained, the produc-tion of fully ceramic dentures, e.g. of zircon oxide ceramic, will be an in-teresting application.

Contact

Dipl.-Ing. J. Wilkes, Tel.: [email protected]. K. Wissenbach, Tel.: [email protected]

Above: Demonstration com-ponent of ZrO2-based ceramicproduced by selective laser melting.Below: Demonstrator for a fully ceramic dental restorationof ZrO2-based ceramic.


Manufacturing of ceramic components by selective laser melting

5 µm

10 mm

Task

Complex simulation calculations aredistributed over several high-perfor-mance computers. The calculation andthe visualization of the results are con-trolled in real time by means of a com-putational steering system (CSS). Theinternal interfaces for communicationwith the graphical user interface (GUI)can be integrated in existing simula-tions with little maintenance expense.The CS system is designed in such away that the development time for simulations with various model struc-tures is shortened.

Method

The CS system uses a client-serverspawn architecture and communicationis handled by the message passing interface (MPI). On the basis of this architecture, the GUI (client) launchessimulations (server) which the spawnsystem connects with simulations thatare already running. Control com-mands, e.g. for interrupting or termi-nating the simulation process and ex-changing parameter and calculationdata, are implemented through a sui-table protocol. The protocol is encap-sulated in a dedicated library, whichsimplifies integration in existing pro-grams or the creation of new pro-grams. Data exchange with the GUI is conducted by means of associativearrays and functions along the same lines for various programs. Programcontrol data and input masks for theparameters are created in XML format.As various visualizations are requiredfor different simulations, these are based on plug-ins which use the visua-lization toolkit (VTK) based on OpenGL.


The CS system is used to compute meltflow and heat transfer. The complex simulation tasks are put together fromexisting and tested modules. With thedeveloped computational steering sys-tem, a tool is available for producingnew parallelized simulation programsincluding visualization using alreadyexisting modules. This procedure shortens development times for newsimulation programs and supports theanalysis of variants in the modelstructure.

Contact

U. Jansen, Tel.: [email protected]. M. Nießen, Tel.: [email protected]. W. Schulz, Tel.: [email protected]


Computational steering system for parallelized simulation calculations

Above: GUI of the computationalsteering system for visualizing temperature.Below: Flow diagram of the computational steering system(CSS). CSS light blue, simulationblue-gray, spawn light yellow.

Task

With increasing product miniaturization,laser technology today plays an essen-tial role in the production of micro-engineered components and assemblies.Rising quality requirements not onlyset higher and higher requirements for the process technology but also demand quality-assurance measureswhich ensure the reliable recognitionof process faults. For this reason, post-process inspections are frequently con-ducted. A 100-per-cent post-processinspection as a rule entails considera-ble time and effort, however, and so it is often restricted to surface faults.As a result, there is a need for reliableonline detection of welding faults bymeans of in-process control.

Method

The camera-based system for coaxialprocess control (CPC) developed by the Fraunhofer ILT makes it possible toconduct locally resolved observation ofmicrowelding processes with a time re-solution of up to 10 kHz. The key partof the system is a CMOS camera, withwhich the welding process is observedcoaxially to the laser beam by the op-tical processing system. Likewise bymeans of coaxial illumination of theworkpiece surface, it is also possible to detect the phase boundary betweensolid and molten material with a diodelaser. This enables certain physical con-ditions which correlate with processfaults to be identified, e.g. in spot welding.


Using this system, it has been possibleto detect welding faults caused by a concealed gap in the lap weld. Tothis end, the size of the molten bath is continuously measured during thewelding process. By comparing the realcontour of the melt pool with an idea-lized, circular contour, a specially deve-loped algorithm permits robust, real-time-enabled melt pool measurementeven if e.g. splashes occur.

Because a gap in the joint can influ-ence both the pressure conditions inthe key hole as well as the thermalconduction conditions, irregularities in the development of the melt poolcan be detected if such a gap occurs.Compared with conventional techniques,the method offers the advantage thatthe recognition of faults is based onphysical effects and does not rely oncomparing incoming signals with re-ference values. As a result the systemoffers great flexibility and can be usedin a wide range of applications.

Contact

Dipl.-Ing. J. Gedicke, Tel.: [email protected]. B. Regaard, Tel.: [email protected]. A. Gillner, Tel.: [email protected]


Process control in microwelding

Above: Development of themolten bath in the lap weldingof stainless steel sheets withand without a gap in the joint.Below: Measuring the moltenbath by fitting a circular con-tour into the recognized moltenbath geometry.

0,1 mm

0,1 mm

gap size 100 µm

gap size 0 µm

process duration

mel

tpo

ol

Task

Spot welding or spaced spot weldingusing pulsed laser radiation is anestablished process, especially in theelectronics industry, for joining over-lapping connections in series produc-tion. The high production volumes inthis sector (up to 108 p.a.) and thehigh requirements in respect of processcapability (Cpk ≥1.67) call for efficientand reliable methods of process con-trol. The following major causes offaults have been identified:• lack of fusion causing contact

failures in electrical components.• splatter which can lead to faulty

contacts.

The aim is to provide monitoring systems for detecting such faults.

Method

At the Fraunhofer ILT, a process obser-vation technique has been developedwhich uses a camera to monitor theexternally illuminated workpiece sur-face coaxially to the processing laser.With frame speeds of up to 7,000images per second, the melt pool andsplatter outside the molten zone canbe observed (middle figure).

For detecting splatter, an algorithm has been developed which recognizes»dark« round objects on the surfacestructure. By analyzing consecutiveimages the system can differentiatebetween lying and flying splatter. Restriction of the possible maximumand minimum splatter size and thearea of measurement reduces thepseudo-fault rate.

Inadequate fusion is detected by ana-lyzing the melt pool. Its size varies during the weld as a function of thegap between the joining partners;therefore a missing connection can be detected by analyzing the increaseof the melt pool (lower figure).


The techniques for recognizing lack of fusion and splatter can be deployedin spot welding applications where thebeam is introduced vertically. So far,tests have been conducted on copperand steel materials up to a thickness of0.5 mm. The process is currently beingfurther developed for applications withscanner optics.

Contact

Dipl.-Ing. B. Regaard, Tel.: [email protected]. J. Gedicke, Tel.: [email protected]. S. Kaierle, Tel.: [email protected]


Detection of process faults in micro-spot-welding

Above: Optical setup for the coaxial illumination and obser-vation of the workpiece surfaceduring laser welding.Middle: Image of a spot weldingprocess with coaxial external illu-mination. Splashes are detectedusing image-processing algorithms.Below: Development of the sizeof the molten bath in a spot-weld-ing process. Melting takes placemore slowly if the joining partnersare not properly connected.

Task

The use of fiber-guided laser beamsources of extremely high optical qua-lity in combination with miniaturizedbeam guidance and beam shaping systems and tiny visual monitoring systems makes it possible for the firsttime to create laser beam-based gripp-ing and joining systems integrated inconventional high-performance assem-bly units for packaging in electronics.

In the DFG-funded Collaborative Research Centre 440 »Assembly of Hybrid Microsystems«, a miniaturizedscanner system with a size of a match-box is being produced which incorpo-rates innovative scanner mirrors. Be-cause this system is distinctly smallerthan the systems currently available on the commercial market it can be integrated in highly dynamic assemblyunits.

Method

Parameters are taken into account inthe design of the beam path which result from miniaturization of the totalsystem. They include availability of mi-niaturized optical systems, intensitieson the scanner mirrors, and the beamguidance and shaping of various wave-lengths (VIS, NIR, IR). Also, the laserprocesses for welding metals and forwelding plastics entail opposing require-ments for the system as a whole, suchas imaging quality, intensities and focusgeometry. The miniaturization of scannersystems for micromaterials processingis limited by the available optical coat-ings of the elements used and by thedimensions of the optical components.Minimal dimensions for usable raw beam diameters are the result.


As a first step, the complete opticalsystem was designed using the ray tracing method. Compared with alreadydeveloped miniaturized projectionscanners, the laser power required formaterials processing and the high reso-lution in the 1 µm range along with ahigh numeric aperture represent a par-ticular challenge. The integration of anexternal illumination source for camera-based process monitoring with a smallerwavelength than the laser wavelengthrequires a chromatic adjustment of thecomplete optical system. The reductionof the raw beam diameter at a minimalfocus diameter of up to 20 µm and a working range relevant for materialsprocessing of 30 x 30 mm2 , as well as a working distance of 50 mm, is adecisive factor in the design of the op-tical system.

Contact

Dipl.-Ing. F. Schmitt, Tel.: [email protected]. A. Gillner, Tel.: [email protected]


Development of a miniaturized scanner system for laser-beam microjoining

Above: Ray tracing of the f-theta focusing optics.Below: Size of a commerciallyavailable scanner comparedwith the development target.


Microwelding of plastics by fiber laser

500 µm

Above: Light-microscope image of two 120 µm-wide weld seamson a sample of polycarbonate.Below: Welded microfluidic com-ponent made of PMMA with acomplex channel structure.

Task

In recent years, laser-beam welding of plastics has become an establishedprocessing technique for many indus-trial applications. It has limitations, however, with respect to weld seamwidth and operating speed. New deve-lopments in medical and biotechnolo-gical microsystems have increased therequirements which have to be met inthe laser welding of plastics. The widen-ing of the range of materials used inmicrosystems engineering to includeplastics has both opened up new pro-spects and created new requirementsfor innovative concepts and methodsthat can be applied.

Production techniques are requiredwhich will enable plastics to be reliablywelded at geometries of 100 µm. Onthe basis of a fiber laser and an inno-vative irradiation strategy, a new tech-nique has been developed for the laserwelding of plastics.

Method

In the tests, a fiber laser with a wave-length of 1112 nm and a maximumoutput of 9 W is used as the beamsource. Thanks to its excellent beamquality of M2 < 1.1 a focus diameter of30 µm can be attained for a workingdistance of 100 mm.

The application of an innovative irra-diation strategy for introducing theenergy is required, as the intensity of the focused fiber laser beam (106 W/cm2) is much higher than theusual values for plastics welding (300 W/cm2). By using a highly dynamicrapid circular movement along the direction of feed, welds can be madewithout destroying the material evenat great intensities.


With the new irradiation strategy anduse of the fiber laser, microfluidic com-ponents made of PMMA and PC canbe sealed along the complex weld con-tour with a laser output as low as 3.5W and an operating speed of 2 m/min.The width of the weld seam is lessthan 500 µm, and a cycle time of below 6 s can be achieved with cor-responding scaling of the process para-meters. On the polycarbonate samples,weld seams with a good visual appea-rance can be produced at an output of 8 W and a feed rate of 18 m/min.The weld seam width can be reducedto 100 µm. The new process has greatpotential for use in the large-scale pro-duction of microfluidic components.

Contact

Dipl.-Ing. A. L. Boglea, Tel.: [email protected]. A. Gillner, Tel.: [email protected]

Task

Thermoplastic polymers usually exhibitlow absorption in the visible and near-infrared region of the spectrum. In un-modified condition, the plastics are op-tically transparent or translucent. Laser-beam transmission welding of thesecomponents entails the challenge ofensuring by means of suitable pigmen-tation that the laser light is transmittedthrough the first of the two parts to bejoined and is absorbed in the second.

Method

At present, in the simplest case, atransparent-black combination is crea-ted by admixing carbon black in theabsorbing part. This addition of carbonblack is not possible in cases where the plastics have been colored usingdyes or pigments, or when joining twotransparent plastics, as the carbonblack strongly influences the coloringeffect or transparency. In these cases,an adequate level of absorption can beachieved by using either absorbent in-termediate layers or organic absorberswhich are added to the absorbing part.The absorbers have to be applied tothe component an additional processstep and can influence the color effectof the parts to be joined.


By using innovative high-performancelaser-beam sources, it is possible forthe first time to dispense with addedpigments. Instead, the characteristicsof the laser light are adapted to the intrinsic absorption properties of theplastics. With suitable process control,the advantages of transmission joiningcan be retained without influencingthe surface of the plastic componentsfacing the laser beam. Transparentplastics can also be welded in this waywithout using infrared absorbers. Itmust, however, be ensured that thegreater part of the laser energy is con-verted into heat at the point where thetwo plastic parts meet.

Contact

Dipl.-Ing. M. Poggel, Tel.: [email protected]. A. Gillner, Tel.: [email protected]


Laser welding of thermoplastics without the addition of absorbers

Above: Microfluidic componentmade of TROGAMID (PA PACM12) with a meandering channelstructure.Middle: Detail of channel branching.

500 µm

Right: Transparent mini-housing.Foreground: Welded withoutusing IR absorbers.Behind: Standard combinationtransparent/black.

Task

During laser transmission welding ofplastics, the laser beam widens as itpasses through the upper of the twoparts to be joined, provided that the other part is made of a semi-crystallinepolymer (top image left). This has theeffect of reducing the beam intensity inthe weld zone and increasing the widthof the weld seam. The phenomenon iswell-known but has not been investi-gated previously.

Method

A reliable expression of observations inthe field is that, when passing througha polymer of thickness x, the intensity I(= power/surface area) of a laser beamis reduced according to an exponentialfunction:

where µa represents the loss of intensityresulting from absorption, and µs thereduction in intensity caused by an in-crease in the beam diameter d. To de-termine the value of µs for the materialPA 66, samples of various thicknesseswere prepared, and the intensity distri-bution of a diode laser beam with awavelength of 803 nm was recordedwith a CCD camera after the beamhad passed through the polymer mate-rial (the laser output on the sample positioned directly in front of the CCDchip is approx. 40 mW after a 1:100 re-duction). For each intensity distribution,the beam diameter d is determinedusing the second-moment method,and the value 1/d2, which is propor-tional to the intensity, is plotted as a

function of material thickness. An ex-ponential function is fitted to the mea-sured values and directly delivers thescattering coefficient µs. The scatteringcoefficient thus obtained is unrelatedto the transmittance of the polymer, as the measured beam diameters donot vary as a function of the output.


The scattering coefficient determinedfor PA 66 at a wavelength of 803 nmis 1.18 mm-1. This means that, accor-ding to

the beam diameter d doubles in sizeafter passing through PA 66 with athickness of x = 1.17 mm.

With the components and processesdescribed above, the Fraunhofer ILTthus disposes of a test system for thequalification of materials during laserwelding of plastics.

Contact

Dipl.-Phys. G. Otto, Tel.: [email protected]. A. Gillner, Tel.: [email protected]


Beam widening during laser welding of plastics: Determining the scattering coefficient of PA 66

Above: Transmitted light micro-scope image of a sample 10 µmthick made of semi-crystalline polyamide 66.Middle: Power density distribu-tion of an 803-nm diode laser beam after passing through a 0.2-mm-thick PA 66 sample. Mea-sured beam diameter: 0.68 mm.Below: Same as middle image but with a sample thickness of1.8 mm and a measured beamdiameter of 1.82 mm.

50 µm

Task

Hybrid microsystems often contain discrete components made of differentmaterials, including glass, engineeringceramics or single crystals such as sapphire. These microsystems are often assembled on a silicon substrate whichalso contains the components of elec-tronic circuits. Commonly used me-thods for joining these componentsare silicon direct bonding or anodicbonding, both of which require bond-ing of the entire surface. These joiningmethods inflict a high thermal stresson the components, and are relativelyinflexible when it comes to bondingdifferently shaped surfaces. As an al-ternative to these wide-area methods,laser bonding helps to minimize theheat-affected zone and the associatedwarping by exact monitoring of theenergy deposition.

In addition to being able to join dissi-milar classes of material such as siliconand glass, laser bonding can also beused to join similar materials. By usingabsorbent intermediate layers, the laser radiation is converted into heatenergy at the joining interface.

Method

Selective laser bonding is based on the process of transmission joining.One of the parts is transparent to thelaser light, while the other is absor-bent. Most of the laser beam's energyis converted into heat at the joining interface, thereby heating the area ofcontact.


Selective laser bonding holds great po-tential for application in the packagingof microsystems. It can be utilized atwafer level as part of a bond stationand used to fix or selectively bond sili-con and silicon, for example in micro-electro-mechanical systems (MEMS), orsilicon and glass, for instance in 'siliconon insulator' (SOI) processes. The me-thod of bonding similar classes of ma-terials with absorbent intermediate la-yers can be used for packaging in thefield of display technology. Minimizingthe extent of the heat-affected zoneprotects the functional metal and or-ganic films and electronic componentsin the immediate vicinity of the joiningarea. A set of promising first resultshas been achieved in the bonding ofsilicon and silicon. Good results havealso been obtained for bonds betweensilicon and types of glass with diver-gent coefficients of thermal expansion,such as silica and soda-lime glass.

Contact

Dipl.-Ing. F. Sarı, Tel.: [email protected]. A. Gillner, Tel.: [email protected]


Laser-assisted selective bonding of similar and dissimilar classes of brittle hard material

Above: Silica-glass packagingon a silicon chip.Middle: Bond between glassand glass.Below: Fractured surface of a silicon sample, bonding of silicon and silicon.

Task

Markings in glass are used for a varietyof purposes such as ornamentation,product markings on bottles, measur-ing instruments and medical devices,and even security codes. One techniquealready available for this purpose is laser micro-marking. Such markingsare permanent, inexpensive, and im-possible to forge, but they are colorless(white). One technique for creating colored areas in glass is by forming nano-particles of metal (preferably silver).However, only yellow, red and brownshades can be obtained by this method.An added drawback of both processes(laser micro-marking and the irradiationof metal nanoparticles) is that theybuild up considerable stress in theglass, thus detracting from the stabilityand service life of the marked glass objects.

Method

In order to produce colored markingswithout measurable mechanical da-mage due to induced stresses, glass is doped with special photochemicallyactive ions. The introduced laser light is absorbed by these ions, causing localcoloration (ion coloration). If the laserbeam is focused in the right way, co-lored markings can be etched in glasswithout generating the stresses thatnormally occur when conventional laser methods are used. Suitable glassmaterials and laser light irradiationtechnologies are now being developedand tested.


The glass is modified with ns-pulsedUV light emitted by a Q-switched, frequency-tripled Nd:YAG laser (wave-length 355 nm, pulse duration 10 to80 ns) and with fs-pulsed IR light emit-ted by a mode-coupled Ti:sapphire laser(wavelength 800 nm, pulse duration100 fs) using differing pulse repetitionrates, pulse energies and overlaps bet-ween consecutive pulses.

The soda lime silicate and borosilicateglass materials, which are doped withrare earth and transition metal ions,are colored by the interaction with laser radiation. The laser radiation isabsorbed by optically and photochemi-cally active polyvalent ions, and the optical energy produces fluorescence,ionization and the formation of coloredareas. Depending on the selected laseremission parameters, such as wave-length and pulse duration, the glass is either tinted in the mass (linear ab-sorption, top image left) or volumetri-cally modified to contain 3-dimensionalmarkings (multi-photon absorption,bottom image left). Colored markingscan be produced in transparent andtinted glass as a function of the chemi-cal composition of the glass and the laser and process parameters. The shades that can be obtained are violet,yellow and reddish-brown, each in monochrome. The laser-induced colormarkings in the glass are reproducible,resistant to the effect of heat and ultra-violet rays, and do not crack the glass.

Contact

Dr. A. Horn, Tel.: [email protected] Dr. I. Kelbassa, Tel.: [email protected]


Colored markings in glass

Above: Violet-colored marking insoda lime silicate glass (3 x 3 x 1 cm3)doped with V2VO5 and Ce2O3 pro-duced by linear absorption of ns-pulsed UV laser radiation.Below: Yellow 3-D colored markingin soda lime silicate glass (3 x 3 x 1 cm3)doped with AgO3 produced by multi-photon absorption of fs-pulsed IR laser radiation.

Task

The Fraunhofer Institute for Laser Tech-nology is developing structured planarwaveguide lasers, and has for the first time demonstrated laser activity in structured waveguides made ofNd:Ga5Gd3O12. Owing to their tailoredgeometry and large numerical aperture,planar structured waveguide lasers en-able direct pumping with high-powerdiode lasers.

Method

From process development to manu-facturing, the following steps were carried out on the basis of customers'optical, thermal and geometric specifi-cations:

1. The laser-active material is depositedas a 1 - 5-µm-thick film on lattice-com-patible crystalline substrates by meansof pulsed laser deposition (PLD). Eithercrystalline or amorphous vitreous filmscan be produced as a function of theprocess parameters temperature andprocessing gas pressure.

2. The films are ablated locally using afemtosecond laser to produce parallelgrooves which define the width of theresulting planar waveguides. Featuringrectangular cross-sections, the wave-guides are tailored to the beam cross-sections of the broad-area diode lasersthat serve as the pump source.

3. The length of the waveguides is re-duced to a few mm using a wafer sawand by lapping, and the end faces arepolished to optical quality to minimizecoupling losses.

4. Dielectric mirrors are applied to theend faces of the waveguides to formthe resonator.

5. Using imaging optics, the diode laseroutput is coupled into the resonator.The resonator mirror on the opposite side is semi-reflecting and serves to out-coupling the laser radiation.


Deposition and structuring of the activefilm directly in front of the pump diodeallows highly integrated laser sources to be mass-produced at a low cost.

Together with industry partners, the researchers are testing a variety of laser-active materials for the generation ofdefined wavelengths, especially in thevisible spectral range.

The flexibility offered by both processes(pulsed laser deposition and structuringby fs-laser radiation) in terms of the ma-terials to be processed is of particularadvantage.

Contact

Dipl.-Phys. D. Wortmann, Tel.: [email protected]. J. Gottmann, Tel.: [email protected]


Manufacturing of waveguide lasers by pulsed laserdeposition and fs-laser microstructuring

Above: Emission spectrum of an amorphous waveguide at pump lightintensities below and above the laserthreshold of the waveguide laser.Below: Waveguide laser consisting of a structured planar waveguide between resonator mirrors.

Laser spectrumFlourescence

Wavelength

Inte

nsity

Task

Femtosecond lasers are capable ofcreating coherent periodic structures(or ripples) on the surface of variousmaterials with a periodicity significant-ly below the wavelength of the laserradiation employed.

Potential applications include gratingsfor integrated optics and structuredsurfaces for biotechnical and engineer-ing applications.

Results

On the materials tested (dielectrics,plastics, semiconductors and metals),ripples were produced at intervalsequivalent to 25 - 75% of the wave-length of the laser radiation employed.

The ripples are always aligned perpen-dicularly to the polarization of the laserbeam. Changes in the direction of tra-vel do not influence ripple orientation.

The ripples are coherently continued by application of numerous overlappingpulses. By moving the focus perpendi-cularly to the laser polarization, twoparallel ripples each with a width ofabout 125 nm and a typical depth of100 nm are produced at intervals of approximately 240 nm.

Periodic ripples can also be coherentlycontinued in two dimensions by apply-ing multiple scans with a constant pa-rallel offset.

Contact

Dipl.-Phys. D. Wortmann, Tel.: [email protected]. J. Gottmann, Tel.: [email protected]


Sub-wavelength ripples: Forming periodic nanostructures by fs-laser radiation

Above and middle:Ripples in fused silica. Singlescan with polarization parallelto the direction of travel (above)und perpendicular to the direction of travel (middle); wavelength λ = 800 nm.Below: Coherent continuationof ripples in 2 dimensions onfused silica by application ofmultiple scans with a constantparallel offset of 400 nm.

1 µm

Verfahrrichtung

FokusRiffelabstand 240 nm

Polarisationsrichtung

Polarisationsrichtung

Riffelabstand 240 nm

Verfahrrichtung

1 µm

Verfahrrichtung

Polarisation

Task

As chipless manufacturing process,punching permits the short-cycle batchproduction of complex workpieceswith near-optimum utilization of ma-terials. At atmospheric temperature,the cut surface consists of a smoothcutting zone and a fracture zone. Thelatter is characterized primarily by itsrough surface, which limits its use as a functional surface. By heating thesheet metal material, the smooth cutproportion can be increased to up to100%, irrespective of the material andprocess employed.

Method

The laser technique enables the sheetmetal to be heated quickly and con-trollably. The laser light emitted fromthe fiber of a diode laser is guidedthrough the tool die onto the under-side of the metal sheet via an array of optical elements. The radiant heatemitted by the metal is simultaneouslymeasured and used to control the process.

The tests were carried out on a hy-draulic open-sided press with a pneu-matic feed. In addition to a punch, adie and a clamp, the tool employedconsists of components used for inte-grating the laser output and sensorsand for handling the punched-outparts.

The aim of this project is to createadapted systems and tool engineeringprocesses and, in particular, to masterthe insufficiently researched warm-forming process as well as the short-run manufacturing of componentswith microscale structural features.


A prototype of the newly developed laser-assisted micro-punching systemwas tested on the magnesium alloyAZ31. Sheet magnesium is very diffi-cult to cut and form, resulting in fre-quent chipping on the cut surface atatmospheric temperature. This can beavoided by heating the material.

Toothed wheels are now being pro-duced which can be used, for instance,in micromotors and their transmissionsystems or as parts of mechanical move-ments. The selected wheel geometryfeatures 36 teeth and a diameter of 5 mm. The sheet metal employed is0.5 mm thick. During punching testson magnesium, a completely straightcut was achieved.

Other applications can be envisaged in areas requiring high-quality compo-nents with small structural features. Bylowering the yield stress and activatingadditional glide planes, it is possible toprocess high-strength and brittle mate-rials.

Contact

Dipl.-Ing. J. Holtkamp, Tel.: [email protected]. A. Gillner, Tel.: [email protected]

Above: Punching tool.Below: SEM image of 2 toothedwheels, hot-punched (above)and cold-punched (below).


Laser-assisted punching

200 µm

Task

Photovoltaics is one of the key techno-logies that promise to assure tomorrow’ssupply of electricity, not only in Ger-many but also in many other countriestoo.

One of the pressing needs is to increasethe efficiency of solar cells and solarmodules, and to reduce reject ratesduring manufacture. Paired with thedemand for a dramatically increasedproduction volume, this calls for tech-nologies that allow efficiency-optimizedsolar cells to be manufactured at ratesof over 1000 Si wafers per hour, whileat the same time limiting the quantityof rejects to a minimum. In order tomeet these requirements, an internalFraunhofer research project aims to develop new technologies and de-monstrate them to industry as inlinesolutions. On the one hand, thesetechnologies aim to increase the effi-ciency of solar cells and eliminate theefficiency losses associated with con-ventional manufacturing processes,and at the same time they aim to im-prove the efficiency of the productionprocess itself, thus lowering the rejec-tion rate.


As a non-contact and selective tool,the laser is predestined for use alongthe entire process chain, from the siliconsource material to the assembly ofcomplete solar modules, including va-rious production steps such as separa-tion, drilling, structuring and soldering.In the course of the project, two stagesof the process chain are being testedand optimized at the Fraunhofer ILT. Inthe case of laser drilling, for example,the goal is to achieve more than10,000 drill holes per second with the

help of high-repetition laser beamsources and highly dynamic beam moving devices. For this purpose, theresearchers are implementing a fastbeam-guide system in combinationwith a suitable beam source as part of the project. At present, it is possible to produce 500 drill holes per secondby means of a single-pulse drilling process. A suitable technique for theelectrical contacting of solar cells isthat of laser-beam soldering, due tothe low and locally restricted energyinput involved. By selecting suitablesolders, the joining temperature can bereduced to a minimum, and thanks tothe non-contact process, the solar cellsare not subjected to mechanical strain,unlike with conventionally used bow-type electrodes. A further advantageof the laser-beam soldering process isthat it can be automated. Instead ofthe linear contact employed so far, thecell connectors are linked to the solarcell at 20 contact points. By suitablyselecting the quantity of solder and the surface area to be irradiated, it ispossible to reproducibly set the elec-trical transition resistance required.

Contact

Dipl.-Ing. F. Schmitt, Tel.: [email protected]. A. Dohrn, Tel.: [email protected]. A. Gillner, Tel.: [email protected]


Laser-based solar cell technology

Above: Laser-soldered cell connectors on a solar cell.Below: Hole matrix in siliconwafer.

Eintritt Austritt

25 µm

Task

Deep drill holes with a small diametercan only be produced to a limited ex-tent by laser, and are therefore madeusing alternative methods such aselectro discharge machining (EDM) and electro chemical machining (ECM),which are time-consuming and thusexpensive. The depth to which holescan be drilled by laser percussion drillingis restricted by incomplete expulsion of the molten metal from the base ofthe drill hole and the resulting recastleft inside the hole. When the meltsets, it closes off the bore hole (topimage left). The goal is to overcomethese restrictions, which are due tosystem-specific limitations of the lasersystems employed, by time modulationof the laser beam. The speed of thedrilling process and thus also the depthof the drill holes is to be increased byreducing the occurrence of defectssuch as closure.

Method

By spatially and temporally superim-posing two laser beams, the drillingspeed in stainless steel and aluminumcan be increased by up to a factor of4. In this case, the output of a diode-pumped Nd:YAG solid-state laser is superimposed on that of a lamp-pumpedNd:YAG slab laser. Holes were per-cussion-drilled in different materialthicknesses (5.8 and 10 mm) and thethrough-drill time was measured ineach case.


In conventional percussion drilling (not superimposed) with a slab laser,closure of the drill hole temporarilyhalts the drilling progress and leads toconsiderable fluctuations in the timerequired to achieve drill-through.

If the output of a DPSS laser is super-imposed on the beam, the drill-throughtime is reduced for all material thick-nesses as the DPSS laser output increa-ses. The number and size of closuresoccurring in the drill hole are also re-duced. This results in a higher drillingspeed without changing the diameterof the drill hole.

The results show which temporal in-tensity curve is most efficient for drilling,and can thus be used to develop activepulse shaping laser systems.

Laser beam superposition helps toachieve greater productivity and ensureshigher process reliability owing tosmaller fluctuations in the requiredthrough-drill time. Holes with a mini-mum diameter of 150 µm can be drilled through material thicknesses of up to 10 mm (bottom image left).

Contact

Dipl.-Phys. M. Brajdic, Tel.: [email protected]. K. Walther, Tel.: [email protected]. I. Kelbassa, Tel.: [email protected]


Drill holes with a high aspect ratio

Above: Percussion drilling in a multi-layer system with closure by melt.Below: Longitudinal section of drill holes made with super-imposed DPSS laser radiation in stainless steel 5 mm thick.Drill-hole diameter: approx.130 µm.

0,5 mm

Task

Hot gases subject turbine componentsto extreme thermodynamic stress dur-ing operation. In order to ensure reli-able long-term turbine operation andhigh levels of efficiency at high tempe-ratures, nickel-based superalloy coat-ings are employed in the manufactureof turbine components. In addition,the turbines must also be effectivelycooled. In a process known as effusioncooling, an increase in the density ofthe cooling holes (up to 100 holes percm2) ensures a uniform distribution ofthe coolant fluid over the surface ofthe component concerned. A direct interaction with the stream of hot gasthat would lead to loss of efficiency is thus avoided. The holes are aerody-namically contoured to increase the efficiency of cooling by ensuring thepresence of a uniformly distributedcoolant film close to the surface of thecomponent.

Method

The parameters of the freeform contoured surfaces of the holes arecalculated with the help of flow simu-lations. These data are then transferredto the positioning system via a closedCAD/CAM/CNC chain. After the pro-cess control parameters and processparameters have been established in a test run, the contoured holes areproduced in a two-step process:1. A through-hole is pierced by

percussion drilling, centered on the longitudinal axis of the desired contoured hole.

2. The cooling hole is then cut to its final shape by means of 5-axis trepanning.

The viability of the process has alreadybeen demonstrated on arrays of drillholes and it is being continually im-proved in terms of process cycle times,

the geometries that can be generatedand the reproducibility of the resultsobtained. Depending on the specifi-cations, a variety of hole geometries (e.g. conically tapering or elliptical) can be realized in a range of materialsand material combinations (metals, ceramics, multi-layer systems and com-posites).


• The realization of contoured holes by means of 5-axis trepanning is notconfined to contouring the exit areaof the hole, but can be achieved along the entire length of the hole through the workpiece.

• Holes typically have a diameter of ≥ 0.2 mm and a depth of up to 5 mm.

• The thickness of the recast on the walls of the hole is ≤ 20 µm.

• A closed process chain (including a CAD/CAM/CNC interface) that is capable of realizing variable hole geometries in OEM components is available for the drilling and cutting of contoured holes.

Contact

Dipl.-Ing. K. Walther, Tel.: [email protected]. I. Kelbassa, Tel.: [email protected]


Drilling and cutting of contoured holes

Above: Section through a holein a multi-layer system (heat in-sulation layer yttrium stabilizedzirconium, corrosion resistantlayer MCrAlY, nickel superalloyCMSX-4), showing the flowvectors of the hot gas (red) and the coolant (blue).Below: Exit surface of con-toured holes in a multi-layersystem.

Above: Laser-drilled contouredholes in high-pressure-turbineblades, Source: MTU Aero Engines.

2 mm

Task

When using a Nd:YAG laser for per-cussion drilling, it is not possible to determine the exact number of pulsesrequired to completely drill throughworkpieces having a thickness rangingfrom a few millimeters to several centi-meters. This is due to instabilities inthe process such as pulse-to-pulsefluctuations. The number of pulses istherefore normally set at a (higher) levelthat is certain to achieve complete penetration of the workpiece, whichusually means that the piece is irradiatedwith a number of ‘extra pulses’ after it has been drilled through. The use ofa coaxial high-speed camera to deter-mine the exact drill-through point isthe first step towards controlling thenumber of pulses more accurately, inorder to reduce process cycle timesand avoid unnecessary damage to therear wall of the workpiece when drillinghollow objects.

Method

Experiments were carried out to deter-mine the drill-through point for 2-8 mmthick workpieces made of standard Feand Ni alloys. Holes were drilled at aninclination of 0° and 45°. A Nd:YAG laser system with pulse durations of0.5 -2 ms, pulse energies < 12J andprocessing optics with a focal length150 mm was employed. A CMOS ca-mera system with a repetition rate of50 kHz at a resolution of 96 x 96 pixelsand a color resolution of 3 x 8 bits wasemployed for the coaxial high-speedphotography.

The process emissions of molten metal,vapor and plasma were recorded dur-ing drilling and later analyzed. Colorseparations were made of the resultingimages and each elementary color ana-lyzed individually.


There is a distinct decrease in the ave-rage intensity of the process emissionsduring the pulse that completely pene-trates the workpiece. After drill-through, the average intensity neverexceeds the threshold level (see middlepicture, 8th and 9th pulse). The aim of future research is to allow onlinedetermination of the drill-throughpoint during percussion drilling.

The signal-to-noise relationship beforeand after drill-through is most clearlydiscernable in the red band (wave-lengths 600 - 850 nm). In the center of the process emission intensity dis-tribution, a minimum is reached afterpenetration of the workpiece (bottomimage left). Further investigations areto be carried out with the aim of findinga method to establish the diameter ofthe drill hole on the basis of the inten-sity distribution pattern.

There are potential applications for this technique in all areas where high-volume laser percussion drilling is employed, for example in the drillingof cooling holes in gas turbine compo-nents, or the manufacture of filters.

Contact

Dipl.-Ing. K. Walther, Tel.: [email protected]. I. Kelbassa, Tel.: [email protected]


Offline determination of workpiece-penetration during percussion drilling

Above: Longitudinal sectionthrough a percussion drill hole,8th pulse, material: René 80.Middle: Average intensity ofthe sensor signal.Below: False color representationof the intensity distribution ofthe sensor signal.

1 mm

7. pulse

8. drill-through

threshold level

9. pulse

aver

age

inte

nsi

ty

image number

Task

Percussion drilling by means of a laserbeam is an economically attractive pro-cess that is especially suitable for high-volume processing. However, its widerindustrial implementation is hinderedby the tendency of molten metal to re-solidify on the wall of the drill-hole.The formation of this ‘recast’ seriouslyimpairs the quality of the drill-hole andthe efficiency of the drilling process, asthe layer of recast that accumulates onthe drill-hole wall increasingly shieldsthe bottom of the hole from the laserbeam. The ILT was therefore requestedby an end user of the technology to investigate methods for avoiding thebuildup of recast on the drill-hole wall.

Method

A model of the percussion drilling process was employed to analyze theeffect of a number of process variableson the cooling of the molten metal as it flows out of the drill-hole. Severaloptions for heating the wall of thedrill-hole were investigated and theirinfluence on the formation of recastwas analyzed.


The realization of the drill-hole by theexpulsion of metal in a molten state ischaracterized by the acceleration ofmelt that develops at the base of thehole and its subsequent decelerationalong the wall of the drill-hole. Theformation of recast is the result of asteady state that develops in the hole.This steady state is dependant on threemain factors: the heating of the surfaceof the molten metal, heat transmissionwithin the flowing melt and heat dissi-pation in the surrounding material. Thethickness of the film of melt along thewall of the drill-hole, the proportion ofre-solidified melt and the displacementof melt at the entrance to the drill-holeare calculated in relation to the globalparameters of the laser radiation at thebase of the hole. Analysis of the modelindicated that almost all of the moltenmetal can be expelled when not onlythe base, but also the walls of the drill-hole are heated. This is achievedby adjusting the spatial and temporalparameters of the pulse.

Contact

Dipl. Phys. U. Eppelt, Tel.: [email protected]. W. Schulz, Tel.: [email protected]


Efficient expulsion of melt during laser percussion drilling

Left: : Recast (grey) and themolten metal (blue) shieldingthe bottom of the drill-holefrom the laser beam.Right: Almost complete expul-sion of the molten metal byheating the drill-hole wall.

Task

A necessary task when simulating lasermanufacturing processes is the calcu-lation of the propagation, reflectionand absorption of the laser radiationon the surface of kerf or drill-holes.The aim of this project is to investigatethe effect on product quality of themultiple reflections produced as thebeam is repeatedly reflected and reab-sorbed by the workpiece. The customeradditionally required a detailed analysisof the effects of the direction of pro-pagation and the polarization of thebeam. The necessary geometrical-opticalcalculations were carried out with thehelp of a ray tracing technique. Ananalysis of the results will enable allow-ances to be made for wave-opticalphenomena.

Method

A ray tracing algorithm for two-dimen-sional and three-dimensional surfaceswas produced. The distribution andpropagation direction of the beam andthe surface of the component wereapproximated with piecewise linearfunctions. The partial rays (beamlets)were generated by geometrical-opticalslicing and mapped onto the surface of the workpiece using the ray tracingalgorithm. The beamlets are characte-rized by the energy they transport andperipheral beams. When a beamletstrikes the surface, its energy is dividedbetween the surface and those portionsof the beam that are absorbed or re-flected.

Ray tracing in three spatial dimensionsis considerably more complex than intwo dimensions, and involves discretiz-ing the surface of the component andevery beamlet into triangular sections.The number of computations requiredto divide the energy transported by thebeamlet among adjacent triangles isconsiderably greater. The local propa-gation direction of the rays is of consi-derable importance for the calculationof absorption and reflection (Poyntingvector).


The 2-D or 3-D ray tracing programdeveloped by the ILT can be used to investigate the relationship betweenreflections and the formation of qua-lity-relevant features, such as ripplesand adherent dross, in any laser manu-facturing process. During laser cuttingprocesses, multiple reflections play animportant role in the formation ofripples and adherent dross.

Contact

Dipl. Phys. U. Eppelt, Tel.: [email protected]. W. Schulz, Tel.: [email protected]


Effective ray tracing for multiple reflections during laser cutting and drilling

Above: Ray tracing of a divergent beam of power P0. Division into 5 beamlets (power P1 - P5) and direc-tions on the surface.Below: 3-D ray tracing of a cuttingprocess.

Task

There is an increasing need for micro-drilling techniques to produce micro-scale holes in medical devices and en-gineering products, e.g. for ventilation or drug dosing. The diameter of theseholes commonly lies in the region of < 20 µm, drilled in materials with a ty-pical thickness of 50-100 µm. Severalthousand such holes may be required,at a drilling rate of > 100 holes per se-cond. The layout, number and diameterof the holes varies according to the cus-tomer’s requirements, hence the needfor an easily adaptable system.

Method

To achieve the necessary small hole dia-meters, the method employs a frequen-cy-tripled Nd:YAG laser focused using alens with a short focal length. A galva-nometric scanner is used as a flexible,rapid means of positioning the laser beam. The workpiece is positioned withthe aid of a 3-axis system.

The arrangement of drill holes in thescan field is transmitted to the softwarevia a CAD/CAM link. Defining the holepattern via a CAD/CAM link makes thisa very flexible solution, with which it ispossible to produce different patternsof drill holes very quickly. Similarly, thesoftware allows the drilling parametersto be adapted to the material and tothe required precision.


This drilling method has been shown tobe capable of drilling holes in a varietyof materials at a rate of between 150and 300 holes per second. The maxi-mum size of the scan field defining themachining zone for simultaneous drill-ing of holes is 10 x 10 mm. If holesneed to be drilled over a larger area, alinear-motion positioning table can beused.

The lowest achievable diameter of thedrill holes lies between 10 and 20 µm.The minimum spacing between thecenter of two holes, without meltingthe metal bridge between them, de-pends on the type of material. The nar-rowest achievable bridge width rangesbetween 8 µm (for titanium or tungsten)and 30 µm (for steel).

At very small hole diameters of 10 µm,it is possible to achieve a transparencyof the metal foil of over 20%.

Contact

Dipl.-Ing. (FH) C. Hartmann, Tel.: [email protected]. A. Gillner, Tel.: [email protected]


High-speed microdrilling of transparent metal foils

Above: Diagonal view of a micro-perforated metal foil. The perforated field measures 7 mm x 7 mm.Middle: Perforated titaniumfoil with drill holes in a triangular arrangement. Foil thickness 50 µm, hole diameter 20 µm.Below: Perforated titanium foil with drill holes in a squarearrangement. Foil thickness 50 µm, hole diameter 20 µm.

200 µm

200 µm

Task

Leak testing forms an essential part of the quality assurance process for packaged forms of pharmaceuticalproducts. To validate and calibrate theleak testing equipment, the productmanufacturers need to prepare refe-rence specimens containing fine holeswith a diameter typically in the orderof 5-100 µm. The drill holes must besmooth and burr-free, to prevent themfrom becoming clogged when insertedin the test equipment. Depending onthe product characteristics and the failure mode, precision drill holes arerequired in different places andthrough different wall thicknesses.

Method

An ArF excimer laser is typically used to produce test holes in disposable packaging specimens (image bottomleft). In the first instance, test holes aredrilled as a means of calibrating the lasersystem. The size and shape of theseholes is examined using a light micros-cope and a scanning electron micros-cope. Then the reference specimensare prepared. The fact that the holesare produced by means of laser ablation,a non-contact process, means that thespecimens can even be handled in asterile environment.


Reference specimens for use in the va-lidation and calibration of leak testingequipment are produced to the dimen-sions specified by the customer. Holesof consistently high quality can be drilled in packing materials such as PE,PP, PEEK or COC to extremely smalldiameters, down to a few micrometers(top image left). The tolerance of theseholes generally lies in the region of ± 1 µm. The edge of the holes is slight-ly rounded, and it can be assured thatthere are no open pores, burrs or looseparticles.

Contact

Dipl.-Chem. P. Jacobs, Tel.: [email protected]. M. Wehner, Tel.: [email protected]. A. Gillner, Tel.: [email protected]


Microdrilling of holes in pharmaceutical packagingfor the validation of test equipment

Above: Test hole drilled in PE.Below: Specimens of products fortesting.

Task

The agronomic properties of plant cellscan be significantly improved by meansof targeted gene transfer (transforma-tion). Transgenic plants grown fromsuch cells demonstrate, for example, a greater resistance to plant pathogensor herbicides, an increased vitamin Aand C content, or later cropping ma-turity. However, conventional methodspresent certain disadvantages, depend-ing on the plant cell, and their trans-formation efficiency typically lies below1%. The aim of the project is to raisethe transformation efficiency to 10%by exposing the cells to light from a laser diode at a wavelength of 405 nm.

Method

A laser diode operating at violet wave-lengths, adapted to an inverse micros-cope featuring transmitted light illumi-nation and fluorescence diagnosis, isused to perform optoporation on thecells. The cells are exposed to laserlight at a tangent to their edge for apredetermined length of time. Pene-tration of a fluorescent dye from thesurrounding medium indicates that per-meabilization (optoporation) has takenplace. The fluorescent marking allowscells in which optoporation has failedto be filtered out, leaving behind a cellpopulation of which it can be expectedthat the cells will express the target gene with a high degree of efficiency.

This project is being carried out in col-laboration with the Fraunhofer Institutefor Molecular Biology and Applied Ecology (IME).


Exposure to laser light makes the cellmembrane temporarily permeable. During this period, it is possible forexogenous matter to migrate from thesurrounding medium into the cell. Thetransient transformation of individualprotoplasts was demonstrated with the aid of a reporter gene (EYFP) (seeimage). Excessive doses of laser lightcause damage to the cell membrane,which results in the death of the cells.The exposure must therefore remainwithin a narrow process window interms of laser output power and dura-tion.

The chief advantages of using a laserdiode rather than an ultrashort-pulselaser are the compact setup, the lowinvestment costs, and significantly reduced time and effort to install andoperate the laser.

The described transformation processenables specifically selected single cellsin a large colony to be transformedand unwanted cells to be eliminateddirectly. By implementing image analy-sis software to determine the position,shape and orientation of individualcells, it is possible to automate the process to a certain degree, with auto-mated positioning of the laser with respect to single cells, and automatedlight exposure.

Contact

Dipl.-Chem. P. Jacobs, Tel.: [email protected]. M. Wehner, Tel.: [email protected]. A. Gillner, Tel.: [email protected]


Laser-diode-assisted transformation of plant cells

Successful transformation of aBY2 protoplast with expressionof the yellow-fluorescing repor-ter gene.

Task

The standard technique of interfero-metry has limited usefulness in dy-namic process monitoring because itgenerally only allows quantitative in-formation to be obtained for phasechanges in the order of magnitude ofπ. A novel computer-assisted techniqueinvolving quantitative phase micro-scopy can be used to visualize tran-sient processes on time scales varyingbetween 100 fs and 1.5 µs, typical ofindustrial processes such as laser ma-terials processing. By interpreting thequantitative phase measurements it is possible to derive information onthree-dimensional changes in the geo-metry of microstructures or variationsin the refractive index. The technique is not dependent on the spatial or tem-poral coherence characteristics of thebeam source.

Method

Numerical solution of the transport of intensity equation offers a route to quantitative phase microscopy.The algorithm based on this equation enables the phase information to be reconstructed from three normalbright-field images of an object or aprocess captured on three imaging planes (1 focused and 2 defocusedwith a shift of e.g. ∆z = ± 0,5 - 10 µm).To achieve this, the images are capturedsimultaneously on the three planes

using three CCD cameras. Analysiswith IATIA® Qpm® software simulatesdifferent methods and types of mea-surement used in phase-contrast micro-scopy, such as differential interferencecontrast, Hoffmann modulation con-trast, or Zernike phase contrast (bottomimage left). To obtain a time resolutionof ≥ 100 fs and detection times of up to 1.6 µs, an ultrashort-pulsed laser beam (fs laser beam) and multire-flecting delay lines are used. The sys-tem’s functionality includes computer-assisted synchronization and control oflight-source parameters such as inten-sity, delay, exposure time, synchronizedoperation of the CCD cameras andanalysis of the recorded images usingQPm® software (top image left).


The non-destructive technique can beemployed to visualize processes in lasermaterials processing, such as welding,drilling or ablation. It is equally suitablefor applications in the life sciences,especially the observation of living cellswithout having to add toxic dyes ascontrast agents.

Contact

Dipl.-Phys. I. Mingareev, Tel.: -535ilja.mingareev@ ilt.fraunhofer.deDr. A. Horn, Tel.: -205alexander.horn@ ilt.fraunhofer.deDr. I. Kelbassa, Tel.: [email protected]


Temporally resolved quantitative phase microscopy

Oben: Schematic layout of the phase-contrast microscope.Middle and below: Laser-in-duced modification of a coppersurface. Middle: Image takenusing a reflected-light micros-cope. Below: Zernike phasecontrast image computed usingQPm® software.

10 µm

10 µm

Laser Plant and System Technology

This business area focuses on the deve-lopment of prototype equipment forlaser and plasma-technology applica-tions, as well as on laser systems en-gineering, particularly in the fields of automation and quality assurance.Areas of application embrace welding,cutting, hardening, repair coating, drilling and micro-joining. The systemtechnology offered provides completesolutions for process monitoring, com-ponents and control systems for preci-sion machining, laser-specific CAD/CAMtechnology modules, as well as soft-ware for measurement, open- and closed-loop control and testing. For its work in process monitoring in parti-cular the business area can draw onextensive and, where required, patent-protected know-how. In this sector nu-merous systems have already been li-censed for companies. Target marketsinclude laser equipment and compo-nent manufacture as well as all sectorsof production industry which deploylasers in their manufacturing activity or intend to do so.


Business AreaLaser Plant and System Technology

Development of cladding headsfor laser cladding.

Laser cutting plant for paperboard/polymer laminates (blister packs) 104

Repair of gearbox components by means of laser cladding 105

Autonomous seam tracking for laser welding applications 106

CPC-based process monitoring for high-volume industrial laser welding of camshafts 107

Continuous process monitoring during laser welding of thin aluminum sheet 108

Process monitoring during transmission laser welding of plastics 109

European Laser Institute ELI 110



Contents

Task

The aim of this project is to improvethe performance of a packing machineused to pack small engineering partson blister cards made of a paperboard/polymer laminate (see top picture).Currently, parallel rotating cutters areemployed to separate individual packsfrom the strips of 16 carded blisters as they travel widthwise through themachine. In future, lasers are to beused for this purpose, in order to im-prove the cut quality.

Method

Given the high absorption of infraredwavelengths by paperboard and plas-tic, a CO2 laser (wavelength 10.6 µm)with high beam quality (K = 0.92) wasselected for this application. It can befocused to a beam diameter of appro-ximately 100 µm using a lens with a focal length of 63 mm. This system iscapable of generating beam intensitiesof 106 W/cm2 that are typically neces-sary to cut such materials. The requiredcutting speed was determined as afunction of the specified cycle time of three seconds, the cut-length for an individual blister pack, and the timetaken to position the workpiece. Byemploying multiple cutting headsmounted in parallel, the cutting speedcan be reduced to such an extent thatit is not necessary to mount the headson expensive traveling axes. Using thecutting speed thus obtained as abenchmark, initial experiments werecarried out to establish the necessarylaser output power and the cutting gaspressure and focal position required toproduce a burr-free edge.


On the basis of these experiments, aconcept for a laser cutting system wasdeveloped that would allow the cus-tomer to calculate the cost of replacingthe mechanical cutters by a laser system.This primarily involved selecting an appropriate laser source, traveling axesand a control system, and designingthe beam source, deflection mirror andcutting-head unit arrangement.

In a 4-head cutting unit, a cuttingspeed of 320 mm/s can be achieved,requiring an output of 110 W per beam. A system with a maximum out-put power of 500 W was selected as a beam source. The cut edges aresmooth and burr-free (see bottompicture). The low levels of smoke resi-due, typical when cutting paperboard,are within acceptable limits and can beconcealed with the help of appropriateprinting.

Contact

Dipl.-Phys. G. Otto, Tel.: [email protected]. A. Gillner, Tel.: [email protected]


Laser cutting plant for paperboard/polymer laminates (blister packs)

Above: Blister pack consisting of a preformed polymer film (0.35 mmthick) laminated onto printed card(0.35 mm thick).Below: Cut edge of a paperboard/polymer laminate (0.70 mm thick). Thelaser beam is directed onto the materialfrom above (the polymer side).

Task

A wide range of coating techniquesare employed for the repair of mecha-nical components, for example electro-plating, thermal spraying or conven-tional cladding techniques (plasmapowder, tungsten inert gas welding).Laser cladding offers a number of ad-vantages in comparison to these pro-cedures; these include improved metal-lurgical bonding of the coating and the substrate, low heat transfer to theworkpiece, and the possibility of depo-siting layers of varying thickness from1/10 mm to several mm by utilizingmulti-layering techniques.

The aim of this project was to qualifylaser cladding as a technique for therepair of gearbox components and toimplement and integrate the systemon-site at the customer’s premises,where it would replace existing elec-troplating technology (hard chromeplating).

Method

During the first phase of the project, a variety of gearbox components wererepaired at the Fraunhofer ILT by lasercladding. The results of these repairswere then validated by the customer.On the basis of the data thus gained,the specifications for the system weredrawn up. A customer-designed latheis used for manipulating the parts. Onlyrotationally symmetrical componentsare to be worked.

The main components of the systemare:• a modified lathe with an additional

linear axis for setting the track dis-placement.

• a 2 kW fiber-coupled diode laser and the necessary optical components.

• a Fraunhofer ILT cladding head with an integrated three-jet powder nozzle which allows operation in confined conditions.


A variety of gearbox components wererepaired and, in the process, customer-specific coatings with a hardness of 36 to 60 HRC and a depth of between0.3 mm and 0.7 mm were realized.

The technology was installed and integrated at the customer’s site inRotterdam, where it has been used forrepairing gearbox components sincemid-2006.

The laser cladding process and techno-logy developed by the ILT is also sui-table for repairing other mechanicalparts, turbine components, molds ortools for example.

The project was carried out in collabo-ration with the company Stork Gears &Services in Rotterdam.

Contact

Dr. A. Gasser, Tel.: [email protected]. K. Wissenbach, Tel.: [email protected]


Repair of gearbox components by means of laser cladding

Above: 3-D drawing of the opti-cal system; including collimationoptics, focus optics, CCD cameraand flange-mounted powdernozzle.Below: Repair of gearbox components by means of lasercladding.

Task

Commercial seam tracking systemsmeasure the position of the joint to be welded in advance of the weldingzone. Deviation in the position of thejoint is then compensated for by ap-propriate on-line corrections to the trajectory of the welding path or by an additional axis (linear axis or tiltingaxis). However, the delay resultingfrom the forerun of the sensor must betaken into account when calculatingpath corrections. Such systems are verysensitive to feed rate variations. This isdue to the fact that the seam trackingalgorithm does not receive any infor-mation about the robot hand move-ment after the seam position has beendetermined. Error-free seam tracking istherefore dependent on the followingrequirements:• The path accuracy of the robot must

be within the required positioning accuracy.

• The workpiece must not be displaced or deformed during processing.

• The processing head must not be rotated.

Additionally, every welding applicationhas to be calibrated at a so called ‘golden workpiece’ in order to com-pensate lateral movements of the robot.The feedback to the robot control re-quires laborious integration. The aimof the autonomous seam tracking is todevelop a processing head that reliesexclusively on on-board sensor andactuation systems to correct deviationbetween the robot trajectory and theseam trajectory and therefore is inde-pendently of the robot control systemand prior calibration.

Method

At the Fraunhofer ILT, an optical measuring system was developed thatmonitors the surface of the workpiece

and determines the relative speedbetween the sensor and the workpiecein two axes. In addition, it detects the position of the seam by grayscaleimage analysis. On the basis of this in-formation, the trajectories of the robotarm and the weld seam, and thereforethe necessary correction vector, can becalculated for every point in time. Thecoaxial arrangement of the sensor tothe beam path allows 360°monitoringof the seam position around the inter-action point. Seam tracking is there-fore possible in two axes, obviating the need for a rotational axis. In thissystem, corrections to the beam posi-tion are carried out by a scanner mirrormounted in the beam path (see topphoto).


As the relative motion of the workpieceand the position of the joint are deter-mined simultaneously, a butt joint canbe tracked autonomously. This allowsprecision laser welding to be carriedout either manually or by relatively basic, inexpensive robots incapable ofachieving high path accuracy or withonly limited interfaces. The rough posi-tioning of the processing head is car-ried out by the handling system (robotor manual) and the fine positioning iscarried out by actuators integrated inthe processing head. Processing errors,that can occur when using conven-tional seam tracking systems, resultingfrom inadequate path accuracy of therobot, deformation of the workpieceduring processing or processing headrotation, are therefore eliminated.

Contact

Dipl.-Ing. B. Regaard, Tel.: [email protected]. S. Kaierle, Tel.: [email protected]


Autonomous seam tracking for laser welding applications

Above: Laser welding systemwith autonomous seam tracking.Below: User interface, auto-nomous seam tracking of a si-nusoidal joint. Real-time sensorimage of the workpiece (left);measured course of the seamon the workpiece (right); mea-surement signal of the relativedisplacement of workpiece andprocessing head, seam positionand correction vector (below).

Task

The company LBBZ GmbH carries outhigh-volume laser welding of camshaftsfor the automobile industry. The con-struction of a camshaft can be seen inthe top photo. The weld seam on thecamshaft rod (see close-up) joins therod with the cams. The component isbutt-welded with a CO2 laser system.Quality control is primarily carried outby the machine operator who visuallyinspects each welded part for defects.Badly made camshafts or units withweld defects which fail during lateroperation can have significant follow-up cost implications for the manu-facturer. The identification of defectivewelds is therefore of considerable im-portance. The aim of the project wasto ensure continuous on-line monitor-ing of the camshaft welding processwith the help of the CPC process con-trol system.

Method

The process emissions produced by the laser welding process are reflectedback into the path of the working beam.A proportion of this reflected light is coupled out of the beam path bymeans of a small mirror mounted tothe side of the beam, and mapped on-to the high-speed camera incorporatedin the CPC system via an optical system.This optical system was designed toensure the best possible image quality.The process images are simultaneouslyrecorded and evaluated by the CPCsystem and its analysis software.

A number of evaluation strategies weretested during the project. The most im-portant criteria for selecting an evalua-tion technique were the reliability withwhich defective parts were identifiedand its ability to be used online. Theobjective was to achieve a 100% de-tection rate for defective welds and apseudo-defect rate that was as low aspossible.


The required detection rates could beachieved using an evaluation systemthat compares the recorded processimages with reference images. Thebottom photo shows the evaluation re-sults for a good weld and a poor weld.The amplitude peak visible in the eva-luation signal is typical for a defectiveweld. As this image shows, the systemcan determine the exact point in timewhen the defect occurs. From this it ispossible to directly derive the exact lo-cation of the defect in the weld seam.The evaluation parameters could be set at a level that resulted in a very lowincidence of pseudo-defects and a100% detection rate for faulty weldsin a production run of several hundredcomponents.

A 100% success rate was thereforeachieved with this system. This processis, of course, also transferable to otherlaser welding applications.

Contact

Dipl.-Ing. J. Kittel, Tel.: [email protected]. P. Abels, Tel.: [email protected]. S. Kaierle, Tel.: [email protected]


CPC-based process monitoring for high-volume industrial laser welding of camshafts

Above: Camshaft with laserweld seam.Below: Evaluation results for a good and a poor weld.

Task

The purpose of this project was to investigate a technique for processmonitoring during laser welding of aluminum-polymer composite piping.The main aim was to determine thescope of a camera-based sensor systemfor the detection of welding imper-fections and to assess its suitability foruse in a continuous quality monitoringsystem.

Method

On the basis of an analysis of the dy-namic processes in the welding zone, a selection was made of the imper-fections covered by EN13919-2 whichseemed most suitable for detectionusing imaging techniques; these inclu-ded welding spatter, melt-pool over-flow, holes and lack of fusion.

The coaxial process control (CPC) sys-tem with a secondary light source waschosen as the imaging system. In thefirst instance, the performance limits ofthe imaging process were established,given that high welding speeds are necessary to ensure the productivityand economic viability of the weldingprocess.

Illumination levels and sensor parame-ters were optimized for the monitoringof welding imperfections. The parame-ters of the welding process itself weredeliberately set at levels that wouldprovoke defective welds.


The selected types of imperfection aredetectable using the camera-basedmonitoring unit. The system is capableof visualizing spatter and melt-pooloverflow (see middle and bottom photos) at welding speeds of up to 50 m/min. At higher speeds, motionblur limits the resolution of the imageand thus the size of defects that canbe identified. In such cases, holes canbe detected if the light emitted by the secondary light source is reflected by asurface behind the workpiece. Defectscan be identified on the basis of varia-tions in the surface texture. Pores canonly be detected at diameters equal to or greater than the thickness of themetal sheet.

Lack of fusion in butt joints can be detected if the seam surface is notconcave, because the incident lightfrom the secondary source is reflectedback into space by the curved surface.Processes leading to defects resultingfrom the re-solidification are only de-tectable to a limited extent. Those de-fects that cannot be readily identifiedwith the current arrangement requirealternative illumination concepts.

Image quality can be improved by in-creasing the frame rate and shorteningthe exposure time, thus allowing pro-cess monitoring to be carried out athigher welding speeds.

Contact

Dipl.-Ing. M. Dahmen, Tel.: [email protected]. S. Kaierle, Tel.: [email protected]


Continuous process monitoring during laser welding of thin aluminum sheet

Above: Full-penetration weld at PL = 1 kW, rF = 184 µm, 1050 A (Al 99,5).Middle: Spattering at vs = 28 m/min, s = 0.4 mm.Below: Image perpendicular to the seam surface.

50 µm

deep-penetration weld

full-penetration weld

shee

tth

ickn

ess

welding speed

Task

Transmission laser welding of plasticshas become an established techniquein industrial manufacturing. However,a number of disruptive factors relatingto the component itself, the materialfrom which it is made, or the produc-tion environment, can cause deviationsfrom the ‘optimum processing point’,resulting in defective welds. Thesefactors cannot normally be monitoredduring the welding process. The aim ofthis project is to investigate a numberof optical monitoring techniques for laser plastics welding applications andto develop a monitoring system for in-dustrial use.

Method

The project is being carried out in col-laboration with the industry partnersAmtron GmbH, Huf Tools GmbH Vel-bert und LIMO Lissotschenko Mikroop-tik GmbH and is funded by the ‘Stif-tung Industrie Forschung’, a privatefoundation that finances scientific re-search projects. The aim of the projectis to compare the specific reliability of several monitoring techniques, in-cluding spatially integrated or spatiallyresolved coaxial process monitoring,both through measurement of secon-dary emissions and through observa-tions using a secondary light source.


A processing head with an integratedsensor system for plastics welding applications was designed and con-structed on the basis of a modular op-tical system developed by the Fraunho-fer ILT. The processing head is designedto allow the simultaneous monitoringof heat radiation emitted during thewelding process and the welding pro-cess itself with the help of a secondarylight source. This permits the variousmonitoring strategies to be evaluatedand the sensor signals to be correlated.Welding tests are being carried out onpolycarbonate, polypropylene and po-lyamide. In later stages of the project,strategies for process monitoring and a prototype processing head for indus-trial use will be made available. Theseare intended to meet the need for im-proved quality control and quality en-hancement systems in the field of laserplastics welding.

Contact

Dipl.-Ing. S. Mann, Tel.: [email protected]. S. Kaierle, Tel.: [email protected]


Process monitoring during transmission laser welding of plastics

Plastics welding process illuminated by a secondary light source.

2 mm


European Laser Institute ELI

Short Profile

The European Laser Institute was foun-ded in 2003 through an EU-funded ini-tiative. The ELI mission is to strengthenand further enhance Europe’s positionin the field of laser technology. In addi-tion, ELI aims to raise public awarenessof the significance and prospects of theEuropean laser technology industry. ELIis a network composed of more than20 leading research facilities includingthe Fraunhofer ILT as well as small andmedium-sized companies. This meansthat in addition to its participation inregional and national competence net-works, as an ELI member the FraunhoferILT is also part of an influential, Euro-pean-level laser technology network.

Furthermore, the international co-operation of industry and research,especially in the field of EU researchsupport, is forced by ELI. Amongst others, ELI creates adequate platformsby organizing conferences, workshops,summerschools etc. In the future, thisis supported by the cooperation withthe respective representations (e. g.EPIC, AILU, WLT). A strong cooperationwith the Laser Institute of America(LIA) already exists in the organizationof international conferences (ICALEO,PICALO, ALAW) as well as the Journalof Laser Applications (JLA).

Executive Commitee

The members of the committee representing the ELI are: • Dr. Stefan Kaierle (chairman),

Fraunhofer ILT, Germany• Abdelkrim Chehaibou,

Institut de Soudure, France• Dr. François De Schutter,

Lasercentrum Vlaanderen, Belgium• Dr. Paul Hilton,

TWI, Great Britain• Dr. Wolfgang Knapp,

CLFA, France• Prof. Dr. Veli Kujanpää,

Lappeenranta University of Technology, Finland

• Prof. Dr. José Luis Ocaña,Centro Láser U.P.M., Spain

Contact

Dr. Stefan KaierlePhone: +49 (0) 241 8906-212Fax: +49 (0) 241 [email protected]

Laser Measurement and Testing Technology

The services provided by this businessarea include the development of mea-surement and testing processes and related equipment for material analysisand for geometric testing and surfaceinspection. The requisite measurementand testing software is tailored to customer-specific problem areas. Materialanalysis is based on the deployment oflaser-spectroscopic processes, focusingon the analysis of metallic and oxidicmaterials, identification testing of high-alloy steels, rapid recognition of mate-rials for recycling tasks and analysis ofgases and dust. Special electronic com-ponents are developed for the parallelprocessing of detector signals of highbandwidth.

In biophotonics joint projects are car-ried out in the field of highly sensitivefluorecence detection for protein chipsand laser scattered light measurementsin sub-µl test volumes for protein crystallization. As part of the area’s work on geometric testing and surface inspection components, devices andequipment are being developed for obtaining 1 to 3D information aboutthe geometry or surface properties ofworkpieces. These include processesand special systems for testing the stability of bar and strip products anddevices for the 1D to 3D scanning ofunit goods. Target markets include theproduction and the recycling industrywhich conduct measurement andtesting fast and close to the process.


Business AreaLaser Measurement and Testing Technology

SILAS - Rapid identificationof light metal alloys for automated sorting.

Blue lasers for ultra-high precision triangulation - BLU 114

Scanning system for laser-induced breakdown spectroscopy - ScanLis 115

Rapid laser-based elemental analysis of slag samples 116

Rapid identification of lightmetal alloys for automated sorting - SILAS 117

Rapid laser-assisted analysis of metallic and non-metallic inclusions in steel - REAL 118

Laser analysis of corrosive change in building materials 119

Rapid preparation and analysis of process samples by laser 120

Improved solid-state laser microablation processes with tailored pulse trains 121

Single particle analysis for the separation of minerals during the extraction of primary raw materials - EIGER 122

Characterization of ultrafine dust particulates in industrial process emissions 123

Remote analysis using laser-induced breakdown spectroscopy - TeleLis 124

Optical stand-off detection of explosives and improvised explosive devices (OFDEX) 125

Confocal laser-scanning microscopy with multiphoton excitation 126

Optical coherence tomography (OCT) in intra-operative tissue diagnostics 127

Integrated microfluidic diagnostic systems - IMIKRID 128

MultiLas - a laser endoscope for the multimodal treatment of brain tumors 129

Endoscopic laser coagulation system for the intraoperative cauterization of blood vessels 130

Application system for intracranialphotodynamic therapy - PDT 131

A rational approach to protein crystallization based on optical measuring techniques 132



Contents

Task

The growing demand for dimensionalaccuracy and surface quality, for exam-ple in the steel processing and auto-motive industries, calls for non-contactsensor concepts capable of measuringwith an accuracy in the micrometerrange and below. Systems of this kind must satisfy the requirements of modern flexible manufacturing lines,which includes automated process and quality control, in terms of speed, reliability and ease of use. Compact,non-contact distance sensors operatingon the basis of laser triangulation areeminently suitable for such purposes.

Method

The objective of the project is to developtriangulation sensors having a higherspatial resolution and accuracy than theproducts that are commercially availableat present. The use of blue laser diodesis expected to improve parameters suchas spatial resolution, signal-to-noise ratioand accuracy. An integrated spatial beammodulator is designed to produce

geometrically adapted irradiation patterns on the object being measured.A time modulator is included for thepurpose of enabling time-division multi-plexing and expanding the dynamic range. The sensor is to be constructedon a stable and lightweight optical plat-form. To conclude the project, the newlydeveloped sensors are to be tested forvarious industrial applications.

The project is being carried out with thefinancial support of the German ministryof economics, various industrial partnersand the Fraunhofer-Gesellschaft.


A test setup was constructed in the laboratory for later testing of the sen-sors, and initial measurements were taken to compare red and blue laserdiodes for triangulation sensors. Varioussetup configurations and detectors were tested at the same time, themost important of these being CCDand CMOS detectors which were testedfor their suitability for deployment inthe blue-violet wavelength range.

Contact

Dipl.-Ing. (FH) A. Lamott, Tel.: -133,[email protected] Dr. R. Noll, Tel.: -138, [email protected]


Blue lasers for ultra-high precision triangulation - BLU

Blue laser beams are used for triangulation.

Task

Both in metallurgy and in the metalworking industry, there is a growingneed for rapid alloy analysis methods.This applies not only to the develop-ment of new materials and processes,but also to process and quality control.Laser-induced breakdown spectroscopyis an interesting alternative to conven-tional spectroscopic techniques in thiscontext. Its main advantages are thatthere is no need to prepare the samplesand that no physical contact takes place between the sample and themeasuring instrument.

Method

ScanLis was designed for the analysisof low-alloy steels and of coatings onsheet metals. It was developed as amodular system to cater for these dif-fering applications. The sample standmodule serves to analyze process con-trol samples and reference samples ofthe usual sizes. An extension arm and aUV module make it possible to analyzestrip products, for instance travelingalong a conveyor belt beneath the ex-tension arm. UV modules with operat-ing distances between 100 mm and1000 mm are available. In a later, moreadvanced configuration of the equip-ment, it is planned to include a scann-ing module for raster analysis of sur-faces positioned below the extensionarm.


The system is capable of recordingspectra at a pulse repetition rate of 20 Hz. The laser employed permitsanalyses with single and double pulses.The spectrometer has 30 channels inthe wavelength range from 130 nm to 589 nm. The integrated softwarepackage enables to create and to applycalibrations for a variety of matrices.

Contact

Dipl.-Ing. (FH) R. Fleige, Tel.: [email protected]. R. Noll, Tel.: [email protected]


Scanning system for laser-induced breakdown spectroscopy - ScanLis

Above: ScanLis with samplecarrier module fitted.Below: ScanLis with extensionarm fitted.

Task

During steel manufacturing, a layer of slag is formed on the molten metal.Knowing the composition of the slag isan important factor in monitoring thesteel manufacturing process. Controlsamples taken from the liquid slagusing a probe (see top figure left) haveto be analyzed quickly on site in thesteel plant. Because the distribution ofelements inside the samples is highlyinhomogeneous, this project sets outto investigate and implement improvedlocal averaging methods.

Method

Elemental analysis is performed usinglaser-induced breakdown spectroscopy.A pulsed solid-state laser generates aluminescent material vapor plasma onthe surface of the sample whose radia-tion emission is used for spectrochemi-cal analysis. First, fundamental studiesare conducted for spectral line selectionand element distribution, and improvedcalibration methods are developed fora specific sample type. On the basis ofthese results, a demonstrator for on-site use was set up in the steelworks,thereby minimizing the transport timefor the sample. The results of the laseranalysis were compared with the refe-rence values (see bottom figure left)using control samples.


The algorithms for processing the mea-sured values and for operation controlwere implemented and tested in thedemonstrator, after which the demons-trator was set up and put into opera-tion at the AG Dillinger Hüttenwerkesteel plant. Routine measurements areperformed from the operating panelby the steelworker, who extracts thesample from the dipping probe andplaces it on the sample stand. Themeasuring process begins as soon asthe cover is closed, and the result isautomatically transmitted to the mastercomputer and displayed on the controlstation. The time taken for the analysisis only 1 minute 20 seconds, conside-rably shorter than the approximately 4 - 5 minutes hitherto required for theanalysis of pressed samples, includingthe necessary preparation time.

The work is being supported financiallyby the European Community ResearchFund for Coal and Steel (RFCS) and theFraunhofer-Gesellschaft.

Contact

Dr. V. Sturm, Tel.: [email protected]. R. Noll, Tel.: [email protected]


Rapid laser-based elemental analysis of slag samples

Above: Slag sample taken from the liquid slag layer with a dippingprobe. The sample has a diameter of 20 - 40 mm.Below: In a comparison, the laser analysis closely matches the SiO2

reference values obtained in the moretime-consuming laboratory analysisusing the borate bead method.

reference value

wei

ght

lase

ran

alys

is

measurement of slag samples from productionmeasuring time of laser analysis

regression straight line of the measuring values

ideal curve = angle bisector

weight

Task

Aluminum recycling represents an im-portant source of secondary raw ma-terials. Apart from conserving natural resources, the recycling of used alumi-num makes it possible to achieve con-siderable energy savings, as it requiresonly about 5% of the energy inputneeded for primary production. How-ever, it is only possible to process alu-minum scrap in secondary meltingplants to make high-quality aluminumif the scrap is available in the form ofgrade-pure cast or wrought alloys.

Unfortunately, there are no automatedsorting machines able to separate thescrap into cast and wrought alloys aswell as into various alloy groups as thebasis for material recycling at a high level of quality.

Under the joint SILAS project a new, laser-based identification method isbeing developed which will make itpossible to achieve a high materialthroughput while simultaneously en-suring that the separated fractions areof the highest purity. The aim of theproject is to build a demonstrator tovalidate the functionality of the processunder realistic operating conditions.

Method

The method is based on a combinationof image processing, laser-based deter-mination of geometric features and la-ser-induced breakdown spectroscopy.In addition to recording the geometricand optical characteristics of the sortedmaterial, the chemical composition ofthe individual particles is determined

by laser spectroscopy. The waste mate-rial is then automatically separated intotwo or more fractions on the basis ofselection criteria derived from the entireset of measured values.


Following the integration and synchro-nization of all its component modules,the SILAS demonstrator will enter atest phase which involves evaluatingand optimizing the sorting accuracy of the multi-element analysis method.A core aspect of this optimization pro-cess is to eliminate surface contamina-tion on real scrap samples. This isachieved by preparing the surface priorto each separate LIBS measurement byspatially and temporally adapting thelaser beam output. Subsequently, thematerial composition of a representativepartial volume of the object is analyzedby laser spectroscopy.

There are plans to upgrade the sortingdemonstrator to handle other matricessuch as iron, magnesium and minerals.

Contact

Dipl.-Phys. Ü. Aydin, Tel.: [email protected]. R. Noll, Tel.: [email protected]. J. Makowe, Tel.: -327 [email protected]


Rapid identification of light metal alloys for automated sorting - SILAS

Snapshot of the online analysisof aluminum scrap samplesusing laser-induced breakdownspectroscopy at a conveyerspeed of 3 m/s. The exposure time for this image was 1 s.

Task

The quality of steel is highly dependenton the metallic and non-metallic inclu-sions it contains. These inclusions,whose size typically ranges from 0.1 µmto 100 µm, must be rapidly detected in order to determine the purity of thesteel. The analysis is also required toverify the presence of so-called lightelements such as C, N, O, P and S,which often cannot be detected by theX-ray fluorescence method. As far aspossible, the analysis is to be performedwithout the need for elaborate prepa-ration of the sample.

Method

The laser-induced breakdown spectros-copy method only requires a ground or milled surface. The focused beam ofa diode-pumped solid-state laser scansthe surface of the sample. A smallquantity of the material is vaporized at the focal point of the laser beam toform a plasma. The radiation emittedby the plasma is spectrally resolved andanalyzed by a special software program.


Various steel samples were examinedfor their distribution of metallic andnon-metallic inclusions. Different spec-tral lines were rated for their suitabilityin analyzing the various inclusions. This made it possible to create elementmaps with which inclusions such asMnS can be identified.

The work is being supported financiallyby the Research Fund for Coal andSteel (RFCS) and the Fraunhofer-Gesell-schaft.

Contact

Dipl.-Ing. (FH) M. Höhne, Tel.: [email protected]. R. Noll, Tel.: [email protected]


Rapid laser-assisted analysis of metallic and non-metallic inclusions in steel - REAL

Above: Section of an elementmap for the element Mn.Below: Section of an elementmap for the element S.

Task

Various environmental factors, especi-ally road salt and vehicle exhaust fumes, provoke corrosive changes inconcrete structures such as bridgesand multistory car parks which can ul-timately cause the entire structure tocollapse (see figure bottom right). Thechemicals that cause the most damageare chlorine, sulfur and nitrogen com-pounds. In a joint R&D project with industrial partners and other public-sector research groups, a process isbeing developed to allow engineers to determine the depth to which theseelements have penetrated the struc-ture. This is to be followed by the con-struction of a transportable measuringdevice for rapid on-site analysis.

Method

Laser-induced breakdown spectroscopycan be used to analyze practically anymaterial, even for the presence of hard-to-detect elements such as chlorine orsulfur. A pulsed focused Nd:YAG laseris used to generate a plasma at the sur-face of a drilled concrete core sampleand the element-specific line emissionsare measured. The laser parametersand the test environment (pressure,shielding gas) are optimized so as toachieve the detection limits for chlorineand sulfur required for the renovationof building structures. The depth profileis obtained by scanning the drilling core.


For the detection of chlorine, thespectral line at 837.6 nm proved to bethe most suitable. The upper figure onthe right shows how the averaged lineintensity ratio of the analyte line IC1 tothe matrix line ICa varies as a functionof chlorine content. With the presentstate of the art, it is possible to detectchlorine concentrations of 1% andgreater.

The project is being conducted withthe financial support of the Germanministry of economics, various industrialpartners, and the Fraunhofer-Gesell-schaft.

Contact

Dr. H. Balzer, Tel.: [email protected]. R. Noll, Tel.: [email protected]


Laser analysis of corrosive change in building materials

Above: Variation in the spec-tral line ratio ICl837,6/IICa849,9

as a function of the chlorine concentration in cement.Below: Damage to a concreteceiling as a result of corrosioncaused by chlorine compounds.

concentration weight

Task

In the control of steel manufacturingprocesses, it is very important that the elemental analysis of productionsamples should be carried out rapidly,allowing downstream metallurgicaltreatment to proceed without delay.Currently employed methods such asspark-discharge optical emission spec-trometry, combustion analysis and X-ray fluorescence analysis necessitate time-consuming preparation of thesamples using mechanical processessuch as milling and grinding. Underthe joint ATLAS project a demonstratoris being developed as an alternative tothe conventional two-step process ofmechanical sample preparation followedby elemental analysis with spark-dis-charge optical emission spectrometry.Instead, a single laser-assisted inspec-tion system is employed. By eliminating various intermediate stages, the newmethod can significantly improve theproductivity of the steel manufacturingprocess. In the final phase of the pro-ject, the demonstrator will be tested ina steel plant.

Method

The laser method performs both tasks:preparation and analysis. First the scalelayer is removed locally by time-modu-lated scanning laser ablation and thenthe bulk material is analyzed using thetechnique of laser-induced breakdownspectroscopy. The laser method is non-contact and relatively maintenance-free by comparison with conventionalmilling and grinding.


By directly combining scanning laserablation of the scale layer and subse-quent material analysis by means of laser-induced breakdown emissionspectroscopy, it was possible to improvethe accuracy of the analysis results for samples of steel, for instance by a factor of around 100 for carbon content, by comparison with analysiswithout material ablation.

The demonstrator built by the projectteam is capable of performing fully automated analyses at several pointson the scale-covered side of metalsamples inserted manually into thesample holder.

The Laser Laboratory Göttingen andseven other companies are involved in the collaborative project. The workis being conducted with the financialsupport of the Federal Ministry of Economics and Labour, the Fraunhofer-Gesellschaft and the participating companies.

Contact

Dipl.-Phys. J. Vrenegor, Tel.: [email protected]. R. Noll, Tel.: -138 [email protected]


Rapid preparation and analysisof process samples by laser

Above: LIBS calibration withand without prior ablation ofthe scale layer.Below: ATLAS demonstrator.

scal

edsi

de

Without laser ablation of the scale layerWith prior laser ablation of the scale layer

Concentration

Task

The aim is to improve the efficiency oflaser beam microablation during mate-rial processing by increasing the abla-tion rate and quality, while at the sametime reducing the portion of ablatedmaterial in liquid phase. Laser-inducedbreakdown spectroscopy is used to investigate the induced plasma signalfor possible correlation with the volumeof material removed. By studying theplasma expansion and the propagationof compression waves, insights can begained into the dynamics of the laserablation process.

Method

To date, in most laser-based materialprocesses, the laser energy is segmen-ted into uniform, time-equidistant pul-ses such as Q-switched pulses in thenanosecond range at a repetition rateof several times 10 kHz.

By using tailored, time-modulated laserpulse trains, the project goal is to im-prove the material ablation processand the online diagnostics of the plas-ma dynamics without increasing the laser energy input. One approach involves dividing the energy of the discrete laser pulses into pulse burstswith interpulse separations in the nano-second or microsecond range. This hasthe effect of conditioning the surfaceof the sample and the processing envi-ronment.


The use of picosecond dual pulses im-proves the ablation rate by up to 25%by comparison with two single pulseseach equivalent to half the burst ener-gy, or by 50% by comparison with single pulses delivering the same burstenergy. Two ranges can be set for mi-crostructuring with picosecond dualpulses. Range I (interpulse separation∆t < 40 ns): low ablation rate, goodprocessing quality. Range II (∆t ≤ 40 ns):high ablation rate but inferior process-ing quality. The processing quality is comparable to that achieved usingsingle pulses of half the burst energy.

The plasmas generated during micro-ablation are detected using space-resolved measurements, allowing theplasma dynamics and the internalstructure of the plasma to be studied ingreater detail. Plasmas detected at thetime parameters tdelay = 1 µs, tint = 1 µsfeature two distinct areas within theplasma. In the center, emissions of Fe IIspectral lines dominate whereas, on the fringes of the plasma, the highestemission values are recorded for Fe Ispectral lines. The innermost plasmazone has an excitation temperature ofaround 12,000 K, which decreases toaround 7,000 K nearer the outer edges.

Contact

Dipl.-Ing. (FH) C. Hartmann, Tel.: [email protected]. C. Gehlen, Tel.: [email protected]. A. Gillner, Tel.: [email protected]. R. Noll, Tel.: [email protected]


Improved solid-state laser microablationprocesses with tailored pulse trains

Above: Ablation depth as afunction of interpulse separationfor a microstructuring processusing picosecond double pulses.Below: Intensity distribution of an Fe II spectral line (λ =261.76 nm) in plasma. The ion line is most intense in theinnermost plasma zone (Eb =2 mJ, ∆t = 1 µs, tint = 1 µs).

Surface of the sample

Laser beam axis

ablation deptgh single pulse

pulse distance

abla

tion

dept

h[µ

m/la

yer]

Task

The low price of construction materialsand bulk natural raw materials such as limestone makes it uneconomical to transport them over long distances.The site where they are extracted andprocessed has to be as close as possibleto the end consumer. After extractionfrom the natural deposit, the mineralof economic value usually has to be separated from inferior accessory andinter-grown rock. However, becausetraditional separation methods are notalways suitable, a R&D project hasbeen set up to develop a novel, laser-assisted sorting process that operateseconomically and automatically andcan be used to characterize and sortsolid primary raw materials accordingto the elements they contain, directlyafter extraction. The project entitled EIGER is a collaborative effort beingconducted by a consortium of two research institutes and six small andmedium-sized enterprises.

Method

The approach developed for rapididentification and sorting of the rawmaterial combines image processing,laser geometry measurement, and a sensor system based on the use of laser-induced fluorescence and break-down spectroscopy. After reducing andfractionating the material, its geome-trical-optical characteristics are recordedand analyzed using image processingalgorithms. In the next step, the che-mical composition of the single parti-cles is determined by laser spectros-copy. Finally the material is ejected, separated into two or more fractionson the basis of selection criteria de-rived from the entire set of measuredvalues.

The project goal is to build a pilot-scaledemonstrator capable of testing thefunctionality of the sorting process under close-to-real-life conditions.


The sorting process is initially beingtested on limestone and dolomite, or minerals with a high MgO content,and the results are being validatedusing typical samples from a variety of natural deposits. The requirementsfor industrial application are that thesystem should achieve a mass through-put of 150 t/h with a yield of 90 - 95percent and a product purity of > 95percent.

In the second stage of the project, LIBS experiments have been conductedon static MgO reference samples andon limestone and dolomite samples extracted from quarries in Hastenrath,Kornelimünster and Iran. The focus ofthese experiments lay on the influenceof the laser pulse energy, variations in the number of pulses within a laserburst, and the evaluation of singleevent spectra, and furthermore thespatial separation of the laser beamand the effect of wetness on the mea-surement results.

The project is being conducted withthe financial support of the BMWA,the participating SMEs and the Fraun-hofer-Gesellschaft.

Contact

Dipl.-Phys. Ü. Aydin, Tel.: [email protected]. R. Noll, Tel.: [email protected]


Single particle analysis for the separation of mineralsduring the extraction of primary raw materials - EIGER

Above: UV-illuminated mineralsample with tungsten contentrevealed by fluorescence.Below: Cross-section throughthe same mineral sample show-ing inhomogeneous tungstenlayers.

Task

Air pollution with fine and ultrafinedust particulates has recently becomerecognized as one of the main publichealth risks. Significant sources of an-thropogenic particulates are vehicular traffic and industry.

Extremely small nanoscale particulatesrepresent an elevated health risk be-cause their size allows them to pene-trate the furthest into the human or-ganism. At the same time, these aero-sol particulates are the most difficultfor measuring instruments to detect,hence the pressing need for further re-search. This project concerns a methodfor determining the composition ofparticulates, with particular emphasison the concentration of heavy metals.

Method

Two methods of measurement arebeing developed on the basis of laser-induced breakdown spectroscopy forthe chemical analysis of the particu-lates. In the first method, the particu-lates are collected on filters, classifiedby size, and then analyzed in the labo-ratory. In the second method, singleparticulates are analyzed onsite, directlyin the air stream. This latter method also permits rapid online characteriza-tion.

To obtain reliable measurement results,it is necessary to produce samples andaerosols that enable the test instru-ments to be calibrated for all relevantelements over a range of concentra-tions that varies by several orders ofmagnitude.


Preliminary results of tests conductedon emissions from steel factories indi-cate, for example, an elevated contentof lead, cadmium and copper in parti-culates of up to 100 nm in diameter,whereas higher concentrations of othermetals appear to be found in largerparticulates. In other words, the che-mical composition appears to vary as afunction of the size of the particulates,allowing a correlation to be drawnwith the health risk associated with the different types of emission.

The results of the project will be usedto develop emission-reduction strategiesfor the industrial plants under study.The method can also be employed uni-versally in other branches of industry,engine development and nanotechno-logy.

The project receives financial supportfrom the European Union’s ResearchFund for Coal and Steel (RFCS) and theFraunhofer-Gesellschaft.

Contact

Dr. C. Fricke-Begemann, Tel.: [email protected]. R. Noll, Tel.: [email protected]


Characterization of ultrafine dust particulatesin industrial process emissions

Above: Particulates collectionmethods based on impactorswith thin sheets of aluminum.The dark areas with a diameterof < 1 mm indicate accumulationsof particulates.Below: Laser spectroscopy me-thods can be used to analyzeboth particulates collected onfilters and airborne particulates.

Task

Laser-induced breakdown spectroscopyis a versatile analytical method that canbe used to measure the elementalcomposition of gases, liquids, solidsand dust quickly and accurately with-out physical contact. This direct formof laser analysis is used in environmen-tal engineering (e.g. water and air qua-lity), steel manufacturing (process mo-nitoring, quality assurance), metalwork-ing (seam tracking, verification in-spection), biomedicine, the detectionof explosives and hazardous chemicals,and art restoration. Many of these ap-plications call for a mobile system toenable field use and measurementover long distances.

Method

A flash-lamp-pumped solid-state laseris expanded by a telescope and auto-matically focused on the target up to12 m away. The generated plasmalight is guided via a coaxial large aper-ture telescope to a CCD spectrometerproviding continuous spectral analysisin the 175 - 520 nm range. The systemcan be swiveled vertically and horizon-tally through ± 45º and folded up fortransport.


TeleLis is a mobile analysis system of compact design, capable of beingquickly focused on the target object. A pilot laser beam and an autofocusfeature help to find the correct positionwith respect to the target.

For ease of transport, the system ismounted on a trolley that also protectsthe equipment against environmentaldisturbances such as jolting or splash-water. A monitoring system surveys theoperation of all TeleLis components andlogs the system status by means ofcontrol software.

The system can record either full spec-tra at a frequency of 1 Hz or individualspectral lines at 10 Hz. Analysis can be performed using both single anddouble pulses, enabling element con-centrations down to 0.1% and lowerto be detected.

TeleLis is ideally suited for applicationswhere it is impossible or impractical toaccess the measurement object directly,for example when measuring concen-trations of hazardous chemicals.

Contact

Dipl.-Ing. (FH) A. Lamott, Tel.: -133,[email protected] Dr. R. Noll, Tel.: -138, [email protected]


Remote analysis using laser-induced breakdown spectroscopy - TeleLis

Above: A TeleLis system ready to perform measurements.Below: Calibration curve for themagnesium content in aluminumalloys, measured at a distance of 5 m. The low spread of the datapoints enables quantitative mea-surements to be obtained even ata considerable distance.

Task

Terrorist attacks have been on the risefor the past several years, particularlyin the form of car and suitcase bombs.So far, there is no system available thatcan detect such »improvised explosivedevices« (IEDs) from a safe distance.

Furthermore, there is a great demandin the civil and environmental protec-tion sector for systems capable of re-mote chemical analysis. These couldhelp to monitor emissions or provideassistance when dealing with accidentsinvolving hazardous chemicals, forexample in the petrochemical industry.

Method

Four Fraunhofer Institutes have joinedforces to develop a system for thestand-off detection of hazardous andexplosive materials, based on severaloptical methods that complement oneanother.

The Fraunhofer ILT, for its part, is usinglaser-induced breakdown spectroscopy,a technique which enables high mea-surement frequencies and allows theelemental composition of a material to be determined precisely even over a distance of several meters.

On the basis of experience gained bythe Fraunhofer ILT in laser analysis overdistances of up to 12 meters, the re-searchers are developing methods anddata analysis algorithms that will allowthem to detect the slightest traces ofexplosives even over distances of up to50 meters.


Initial tests carried out on ammoniumnitrate, one of the main componentsof ANFO explosives, show that laser-induced breakdown spectroscopy canhelp to detect small amounts of nitro-gen-containing compounds over a distance of 5 meters, even in the pre-sence of atmospheric nitrogen.

The project is being implemented withthe financial support of the Fraunhofer-Gesellschaft.

Contact

Dr. P. Jander, Tel.: [email protected]. R. Noll, Tel.: [email protected]


Optical stand-off detection of explosives and improvised explosive devices (OFDEX)

Detection of ammonium nitrateover a distance of 5 m.

Task

Confocal laser-scanning microscopyhas become established as a versatilemeasuring technique for the opticalanalysis of fluorescence-tagged or re-flective samples in high spatial resolu-tion. It is used primarily for examiningcells and tissue. By treating specificparts of the sample with fluorescentdyes and scanning it at several diffe-rent wavelengths simultaneously, it ispossible to obtain structural and func-tional information with an extremelyhigh spatial resolution.

Method

The high spatial resolution is achievedby using lenses with a high numericaperture (NA = 1.4) and mapping themeasuring signal on a pinhole aperturewith a diameter of only a few micro-meters in the image plane. High-speedgalvanometric scanner mirrors redirectthe laser beam with a 2 kHz line fre-quency to generate two-dimensionalmicroscopic images. High-resolutionthree-dimensional images can be ge-nerated with the aid of a z-scannerthat axially displaces the position ofthe scanning laser focus. A new-gene-ration laser scanning microscope incor-porates a direct diode-pumped femto-second laser developed at the Fraun-hofer ILT, making it possible to excitedyes in the UV range with multiphotonprocesses. In this way, microscopeexaminations of deep tissue layers orstrongly scattering tissue can be per-formed.


Confocal microscopy is used at theFraunhofer ILT primarily where there isa need to detect weak signals with ahigh signal-to-noise ratio in femtolitervolume samples. Penetration into dee-per organic layers is limited due toscattering and absorption of the emit-ted fluorescence. Ultra-short pulses inthe femtosecond range and the asso-ciated high photon densities permitthe excitation of multiphoton proces-ses in the laser focus, so that fluores-cence can only occur at those points.This effectively suppresses bleaching of the sample. Since infrared radiationis not so widely scattered, this methodallows even deeper-lying tissue layersto be examined.

Contact

Dipl.-Phys. T. Schwendt, Tel: - [email protected]. R. Noll, Tel.: [email protected]


Confocal laser-scanning microscopy with multiphoton excitation

Above: Directly diode-pumpedfemtosecond laser for the exci-tation of multiphoton processes.The laser developed at theFraunhofer ILT is compact andeasy to use.Below: Fluorescence image oftriple-dyed fibroblasts (connec-tive tissue cells) generated withthree excitation wavelengths.λ = 488 nm, actin filaments(blue), λ = 543 nm, mitochon-dria (green), λ = 633 nm, cellnucleus (red).

Task

Optical coherence tomography (OCT)is an imaging technique which allowshigh-resolution 3-D tomographyimages to be created during surgery.Based on interferometric measure-ments, this technology permits the de-tection of structures with a depth reso-lution of just a few micrometers. Thepenetration depth lies at about 5 mm,depending on the tissue being exa-mined. In the medical field, OCT isused as a marker-free, diagnostic tech-nique for distinguishing morphologi-cally between different types of tissue. One specific area of application is thedetection and measurement of bloodvessels more than 50 µm in diameter,so that the cauterization of such vesselsby laser coagulation can be monitoredduring surgery.

Method

The OCT system's beam source is a super-luminescence diode with anemission wavelength of λ = 1300 nm.For an interoperative diagnosis, themeasuring beam is coupled into an en-doscope via an optical fiber and focusedon the tissue to be examined. The beam sweeps the surface of the tissue,performing a deep scan at 200 diffe-rent measuring points each secondwith an axial optical resolution of appro-ximately 10 µm. This is equivalent to a digital resolution of 3000 pixels perdeep scan. The OCT system has an axialmeasurement range of about 9 mm in air, but is reduced to approximately2 mm in tissue due to light absorption.


In a series of validation experiments,cross-section images were taken ofvessels inside a tissue sample. Theimages were made by moving thesample on a microscope stage belowthe measuring beam. A clear contrastcould be observed between the vesselsand the tissue surrounding them. Withthe help of a software program speci-ally developed for OCT diagnosis, themeasurement data can be displayedeither as 2-D sections or 3-D objects.Image sequences can be used to eva-luate changes in the vessels' geometry,for example after thermal interactiondue to irradiation with laser light.

In addition to medical applications, optical coherence tomography is alsoused in production engineering. It isparticularly well suited to measuringthe thickness of films on glass andplastic parts, due to its high axial reso-lution and wide measurement range.Films more than 20 µm thick can bemeasured accurately to within 1 µm.This requires only the smallest of diffe-rences in the refractive index at the interface between two consecutive layers.

Contact

Dipl.-Phys. S. Hölters, Tel.: [email protected]. R. Noll, Tel.: [email protected]


Optical coherence tomography (OCT) in intraoperative tissue diagnostics

Above: Cross-section image of a blood vessel taken with the OCT measuring system in a pig's heart; vessel diameter650 µm.Below: OCT image of a three-layer plastic laminate system.The middle layer is 270 µm thick,and the total thickness of thecomposite material is 4.1 mm.

10 mm

Task

In the interdisciplinary joint project IMIKRID, researchers will develop andvalidate a novel technological platformfor the development of custom-builtintegrated systems for in-vitro diagnos-tics offering an extremely high degreeof sensitivity (10-12 bis 10-13 mol/l).

Method

The key component of this diagnosticsplatform is a microfluidic chip with cir-cular-flow micro-channels that conducta solution containing the analyte mole-cules to be detected. Inside the micro-channels of the silicon chip there arefour independent single-molecule-sen-sitive biosensors, each based on a dif-ferent sensor technology. Three of thesensors employ electrochemical mea-surement techniques, while the fourthuses fluorescence to detect the analytes.All of the sensors have nanoscopictransducer surfaces coated with speci-fic receptor molecules that bind withthe analytes. Specific bonds made bythe transducers can be detected eitherby electronic amplification (seFET), en-zymatic catalysis (nano-enzyme elec-trodes), measuring of redox potential(cyclic voltametry) or fluorescence (micro-optical fluorescence sensor), depending on which sensor techniqueis used. Multifunctional nanoparticlesact as signal amplifiers in the process,with directionally coupled receptormolecules and transducers with a highquantum yield or a high redox poten-tial. In the IMIKRID project, the Fraun-hofer Institute for Laser Technology ILTis developing a confocal single-mole-cule detector with integrated opticaltweezers that can be used to move nano-scopic sensors with sub-micrometer ac-curacy towards the transducer surfaceswith which they interact. This allows

single-molecule events to be reprodu-cibly triggered at the sensors and thesignal responses to be tested. A furtherfunction of the single-molecule detectoris to position nanoscopic receptor sen-sors in the microfluidic system andmeasure the specific bonding of in-dividual analyte molecules at thesesensors. This will optimize the flow behavior of the fluid and keep analysistimes short.


Illnesses with a high mortality rate,such as cancer and cardiovasculardiseases, can be treated successfully ifthey are caught at an early stage. Bydeveloping an improved early-diagno-sis system based on molecular markers,which are present in very small con-centrations in blood serum, patients’chances of recovery and quality of life can be significantly increased. TheIMIKRID detection system currentlybeing developed for this purpose candiagnose marker concentrations in thesingle-molecule range down to below10-12 mol/l.

The R&D activities of the IMIKRID project are supported by the GermanFederal Ministry of Education and Research (BMBF) and are being imple-mented together with partner institutesof the Fraunhofer-Gesellschaft and theInstitute for Micro Sensors in Erfurt.

Contact

Dr. A. Lenenbach, Tel.: [email protected]. R. Noll, Tel.: -138 [email protected]


Integrated microfluidic diagnostic systems - IMIKRID

Above: A microfluidic sensorchip with electrochemical sen-sors, data processing electronicsand a micro flow cell,Source: Fraunhofer Institute forApplied Information TechnologyFIT, Biomolecular Optical Sys-tems department.Below: Confocal detection sys-tem for single-molecule diag-nostics with an optical interfacefor integrating optical tweezers.Diffusion-based detection limitfor fluorescence-tagged biomo-lecules in solution at concentra-tions of c = 10-11 mol/l.

Task

MultiLas is an endoscope designed forthe minimally invasive local treatmentof intracranial tumors through keyholesurgery. By employing five different ra-diation sources in a single endoscope,brain tumors can be ablated accurate-ly, blood vessels can be cauterized andmicro-metastases can be selectively destroyed by means of photodynamictherapy (PDT).

Method

MultiLas operates on the basis of anendoscope with a micro-optical chan-nel 2.7 mm in diameter which guidesthe therapeutic and diagnostic laserbeams into the surgical cavity. Themeasuring radiation generated in thesurgical cavity to monitor the therapyprocess is gathered by the same micro-optical channel and mapped onto adetection system. Tumors with a maxi-mum diameter of 50 mm are ablatedfrom the center to the perimeter witha picosecond laser (Ep = 2 mJ, λ =532 nm, f = 10 kHz). The ablated frag-ments of tissue are removed from thesurgical cavity by a rinsing and suctionsystem integrated in MultiLas. Prior to ablation, a continuous laser beamsource (P = 30 W, λ = 1064 nm) cau-terizes the blood vessels supplying thetumor by means of laser coagulationto preclude internal hemorrhaging. Toensure that endoscopic tumor therapyis safe and precise, it is essential thatboth ablation and coagulation be re-liably monitored online. This is doneusing fluorescence diagnostics to dis-tinguish between cancerous and healthy

tissue, and optical coherence tomo-graphy (OCT) to detect and measureblood vessels. The plasma glow gene-rated during tissue ablation helps tomonitor the focus of the ablation laserrelative to the tissue. Fluorescence ex-citation takes place at 405 nm, whileoptical coherence tomography is car-ried out at 1300 nm.


The MultiLas endoscope technologywas developed in a collaborative pro-ject together with several small andmedium-sized companies. In addition,the fluorescence diagnostics and OCTtechnique were successfully validatedusing in-vitro models in combinationwith the endoscope. On the basis oftheir fluorescence, cells were detecteddown to single-cell level, and geome-tries of vessels 300 µm to 700 µm indiameter were displayed. In a separatetest configuration, coagulation experi-ments were carried out under the opto-mechanical boundary conditionsof the laser endoscope in order to eva-luate suitable coagulation parameters.

The development of MultiLas is sup-ported by the German Federal Ministryof Economics and Technology and is being implemented together with a clinic and several industry partners.

Contact

Dr. A. Lenenbach, Tel.: [email protected]. R. Noll, Tel.: [email protected]


MultiLas - a laser endoscope for the multimodal treatment of brain tumors

Above: Endoscope of the Multi-Las demonstrator with an outerdiameter of 5.5 mm. Inside itthere is a micro-optical channeland a rinsing and suction sys-tem for removing ablated tissuefrom the surgical cavity. The fivetherapeutic and diagnostic laserbeams are guided into the sur-gical cavity via the micro-opticalchannel.Below: Image of cultivated glio-ma cells taken by the MultiLasfluorescence module. Thanks totheir fluorescence signal (greento red), individual cells can beclearly distinguished from thebackground (shown in darkblue). This single-cell sensitivityallows tumors to be detected on a scale of approx. 30 µm.

50 µm

Task

During endoscopic surgery, blood ves-sels must be cauterized prior to tran-section in order to prevent internal hemorrhaging. To this end, the Fraun-hofer Institute for Laser Technology isdeveloping a laser coagulation systemwhich allows endoscopic, contact-freecauterization of blood vessels.

Method

An Nd:YAG laser with an emission wave-length of λ = 1064 nm and a maxi-mum cw output power of P = 28 W isemployed for laser coagulation. Duringminimally invasive surgical procedures,the laser can be introduced into thesurgical cavity with the help of an en-doscope tube. The laser beam itself isfocussed onto the vessel to be caute-rized by means of a short-focal-lengthlens mounted on the tip of the endos-cope. The success of laser coagulationrelies on the optimization of a numberof parameters depending on the dia-meter of the blood vessel to be caute-rized and the rate of blood flow withinthe vessel. The most important para-meters determining successful coagu-lation are the length of time the tissueis exposed to radiation, the powerdensity of the radiation and the geo-metry of the area to be irradiated. The diameter of the thermal interactionzone can, for instance, be adjusted byvarying the distance between the focalposition of the lens and the surface ofthe blood vessel, depending on thediameter of the vessel.

Optical coherence tomography (OCT)is employed to determine the exact location and diameter of blood vessels.This procedure allows the identificationof vessels that are hidden several milli-meters below the tissue surface. As

well as helping to identify blood vessels,OCT can also be used to verify success-ful cauterization. This information isprovided by a series of cross-sectionalimages taken along the length of thecoagulation zone.


The laser coagulation system was vali-dated in a series of trials during whichthe most suitable coagulation parame-ters for a range of blood vessels wereestablished. This was achieved by vary-ing the length of exposure to radiation,the intensity of the radiation and thesize of the irradiated area. The trialswere carried out ex vivo on the vascularsystem of a porcine heart. The vesselswere filled with a native BSA solutionwith a normal protein concentration.Normal circulatory pressure was main-tained in the blood vessels during thetrials. With the help of the ex vivo trials,a »therapeutic window« could beidentified in which laser coagulationresulted in reliable cauterization of the vessel concerned. As not only thegeometry of the vessel, but also bloodpressure and the rate of blood flow inthe vessel have an important influenceon the success of cauterization, the effect of heat dissipation in the inter-action zone is also being systematicallyinvestigated. On the basis of the resultsobtained in such trials, a database ofcoagulation parameters for particulartypes of blood vessels is to be established.

Contact



Endoscopic laser coagulation system for the intraoperative cauterization of blood vessels

Above: Interferogram of a blood vessel before coagula-tion, diameter of the vessel700 µm.Below: Interferogram of the same blood vessel aftersuccessful laser coagulation.

1 mm

1 mm

Task

Despite surgical intervention and radio-therapy, the prognosis for patients suf-fering from aggressive brain tumors,such as malignant gliomas, is generallypoor, with average life expectancies of less than one year. Photodynamictherapy (PDT) promises to improve the effectiveness of the treatment ofgliomas. The therapy is based on theadministration of a photosensitizingagent that selectively accumulates athigher concentrations in tumor cellsand has a cytotoxic effect when exposedto light of a particular wavelength.

Method

An endoscope is being developed to carry out PDT on malignant cerebral glio-mas. With its help, tumor tissue can beirradiated with laser light during a mini-mally invasive surgical procedure. Theendoscope is controlled by a stereotacticguidance system that utilizes CT data to precisely locate the target tissue mass.The inoperable macroscopic remains oftumors or microscopic metastases infil-trating healthy tissue can then be de-stroyed with the help of a laser beamwith an emission wavelength of λ = 635nm that is coupled with the micro-opticalsystem of the endoscope. The irradiationof the tumor tissue can be carried outwith either focused or divergent laserlight. The laser beam is reflected ontothe tissue to be irradiated by a deflectionmirror mounted on the tip of the endos-cope at 90° to its longitudinal axis. By rotating the mirror around the axis of the endoscope, altering the depth of theprobe position or adjusting the frontlens, the laser beam is capable of scann-ing target tissue in three dimensions.


To evaluate suitable radiation parame-ters for PDT on gliomas, a module wasdeveloped that allowed in-vitro PDTexperiments to be carried out on culti-vated glioma cells. The radiation mo-dule is subject to the same opto-me-chanical constraints as the endoscopethat will later be used to carry out thetherapy. PPIX was chosen as photosen-sitizer for the trials. This substance issynthesized in glioma cells after the ex-tracellular administration of 5-aminole-vulinic acid (5-ALA) and has alreadyproved successful in the clinical treat-ment of gliomas. In line with clinicalpractice, 5-ALA was administered tothe cells 3 hours before irradiation. Theexperiments were designed to estab-lish the relationship between phototo-xicity and the radiation dose. Factorssuch as the temporal distribution andthe intensity of the dose were consi-dered. The largest therapeutic effectwas achieved with moderate intensitiesof around 400 mW/cm2 and a dose of 3 J/cm2. This resulted in a cell mortalityrate of 100 %.

Contact



Application system for intracranial photodynamic therapy - PDT

Above: Dose-response curve forexperiments conducted on L18glioma cell cultures with conti-nuous radiation of 400 mW/cm2

and radiation doses between0.5 J/cm2 and 3 J/cm2. Radiationdose for a cell mortality rate of50 %, LD50 = 1.2 J/cm2, radiationdose for a cell mortality rate of90 %, LD90 = 2.9 J/cm2.Below: Radiation module forPDT experiments on glioma cellcultures installed below a sterileworkbench, therapeutic wave-length λ = 633 nm.

Dose-response curve for parallel radiation mode and continuous time regime

Cel

lvita

lity

Dose

Task

The culture of protein crystals is a pre-requisite for investigating the structureof proteins using single-crystal X-raydiffraction. Establishing the optimalconditions under which crystallizationcan take place is a time-consumingand labor-intensive process that pre-sents a major impediment to the pro-gress of investigative work on proteinstructures. The Fraunhofer Institute for Laser Technology collaborated withresearch and industry partners to deve-lop a demonstrator that enables thesystematized culture of single proteincrystals.

Method

The demonstrator built at the ILT ena-bles static and dynamic measurementsof scattered light in protein solutionsto be performed on small volumes. Themeasurement of static light scatteringprovides information about the inter-action of dissolved proteins in the solution, while the measurement ofdynamic light scattering, by analyzingparticle movement within the solution,yields information about the size of the proteins and reveals aggregationprocesses. The sample carrier in whichthe measurements are performed canbe filled by an automated pipette sys-tem, permitting a high throughput andminimum wastage during the measur-ing process. The optical measuringtechniques provide objective evaluationdata that correlate to the probability of crystallization. This data allows themost favorable solution parameters for crystallization (pH value, salt con-centrations, additional and precipitationreagents etc.) to be more effectivelydetermined than was previously possible.


A demonstrator for measuring scatteredlight in small sample volumes wasbuilt. In addition to three precisionaxes for accurately positioning themeasuring point in a small sample volume (typically 500 nl), it incorpo-rates a system of lenses for measuringscattered light and a second system of lenses for polarization microscopy.This enables all phases of crystallizationto be investigated. Static scatteredlight measurements display the poten-tial for thermodynamic interaction be-fore the start of nucleation, dynamiclight-scattering techniques make itpossible to observe the nucleation pro-cess, and polarization microscopy canprovide high-contrast imaging of theprecipitates or crystals after crystalliza-tion or precipitation has taken place. It is possible to distinguish betweenmicrocrystalline and amorphous pre-cipitates. All system components andautomated series of measurements canbe computer-controlled with the helpof specially developed software. Thedemonstrator is currently being evalua-ted in the applications laboratory of apartner institute where the systematiccrystallization and investigation of avariety of proteins is being undertaken.

The work was funded by the Germanministry of economics, several SMEsand the Fraunhofer-Gesellschaft.

Contact

Dr. C. Janzen, Tel.: [email protected]. R. Noll, Tel.: [email protected]


A rational approach to protein crystallization based on optical measuring techniques

Above: Demonstrator for protein crystallization with anautomated pipette system forpreparing samples.Below: Optical systems for po-larization microscopy and lightscattering beneath the samplecarrier.

Patents Germany

Verfahren zum Bohren von metallischen Werkstoffen sowievon geschichteten metallischenWerkstoffen und solchen, die mindestens eine keramische SchichtaufweisenDE 10 2004 014 820 B 4

Verfahren für die Material-bearbeitung und VerwendungDE 100 29 110 B 4

Verfahren zum Aufbau mikro-optischer BauteileDE 102 50 074 B 4

Vorrichtung und Verfahren zumPositionieren und Bestücken einesBauelementes in Oberflächen-MontagetechnikDE 199 48 455 B 4

Verfahren sowie Düse zur Bearbeitung oder Analyse einesWerkstücks oder einer Probe miteinem energetischen StrahlDE 10 2004 018 280 B 4

Montage von Kühlkörpern an LaserkristallenDE 102 26 724 B 4

Frequenzkonvertierte Laser-anordnungenDE 195 36 880 B 4

Verfahren zur Modifizierung von MaterialeigenschaftenDE 102 32 815 B 4

Kompakte UV-Barrieren-entladungslampeDE 10 2005 007 370 B 3

Drehdurchführung für ein Gas-Pulver-GemischDE 10 2005 025 027 B 3

Vorrichtung zum Bohren und für den Materialabtrag mittelsLaserstrahlungDE 10 2005 047 328 B 3

Patents Europe

Verfahren und Vorrichtung zum Bearbeiten von Werkstückenmit LaserstrahlungEP 1 047 522 B 1

Verfahren und Vorrichtung zur Oberflächenbehandlung vonObjektenEP 1 337281 B 1

Strahlführendes und/oder frequenz-konvertierendes optisches Systemsowie Verfahren zur HerstellungEP 1 476 776

Verfahren zum Glätten und Polierenvon Oberflächen durch Bearbeitungmit energetischer StrahlungEP 1 516 068 B 1

Laser-Materialbearbeitung mit hybriden ProzessenEP 1 497 071 B 1

Patents USA

Method and Device for Producing Extreme UltravioletRadiation and Soft-X-Ray RadiationUS 7, 126, 143 B 2

Method and Device for the Generation of Far Ultraviolet or Soft-X-Ray RadiationUS 6, 967, 341 B 2

Patents China

Verfahren und Vorrichtung zumErzeugen von Extrem Ultraviolettund weicher RöntgenstrahlungZL 02807601.X

Patents South Afrika

Verfahren und Vorrichtung zur Durchführung einer Plasma-emissionsspektrometrie2004/10314

International trademark

TECHNOLOGIE BUSINESS TAG TBT900 662

Patent ApplicationsNational

Verfahren und Vorrichtung zur Vermessung geometrischer Merkmale von Objekten mit robotergeführtem Lasersensor10 2006 016 677.9-54

Vorrichtung und Verfahren zum Fügen von wenigstens zweiaus thermoplastischem Material bestehenden Fügepartnern mittels Laserstrahlung10 2006 008 776.3-16

Flexibler Laserapplikator10 2006 039 471.2-51

Erhöhung der Präzision von Handhabungssystemen durch Feinpositioniereinrichtung10 2006 049 627.2

Patent ApplicationsInternational

Verfahren und Vorrichtung zur Vermessung der lateralen Relativbewegung zwischen Bearbeitungskopf und Werkstückbei der Bearbeitung mit einemBearbeitungsstrahlPCT/DE2006/000775

Verfahren zur Vermessung von Phasengrenzen eines Werkstoffesbei der Bearbeitung mit einemBearbeitungsstrahl sowie zuge-hörige VorrichtungPCT/DE2006/000400

Vorrichtung zum Bohren und für den Materialabtrag mittelsLaserstrahlPCT/EP2006/001964

Einbringen von Mustern in matteOberflächen durch moduliertesLaserstrahlpolierenPCT/DE2006/000776


Patents

Kelbassa, I. - 13.01.2006Instandsetzung von Flugtriebwerks-komponenten mittels Laserstrahl-Auftragschweißen

Uckelmann, I. - 31.01.2006Generative Serienfertigung vonindividuellen Produkten aus CoCrmit dem selektiven Laserschmelzen

Klages, K. - 12.05.2006Laserstrahl-Mikroschweißen unglei-cher Metalle durch Nahtschweißenmit gepulsten Nd:YAG-Lasern

Russek, U.-A. - 23.05.2006Prozesstechnische Aspekte des Laserdurchstrahlschweißensvon Thermoplasten

Moiseev, L. - 05.07.2006Pulsed Laser Deposition vonEr:ZBLAN-Schichten für den Aufbau eines integrierten Wellenleiterlasers im grünen Spektralbereich

Giesekus, J. - 14.07.2006Diodengepumpte Laserverstärkermit flachen Lasermedien

Bankowski, MaxHerstellung und Untersuchung von Gradientenschichtwerkstoffenfür den Einsatz im Werkzeugbau

Bao, DanxiaLaserunterstützte Fixierung vonKollagen Matrices

Broder, SilkeEntwicklung und Validierung einerBestrahlungssonde für die intrakra-nielle Photodynamische Therapie

Buerger, AndreasVerbesserung der Umformbarkeitschwer umformbarer Werkstoffedurch lokale Laserbestrahlung

Dolkemeyer, JanAuslegung und Konstruktion eines Laseroszillators zur Charakte-risierung von ytterbiumdotiertenKristallen

Emmerich, AndreasEntwicklung einer Faserkühlung für einen Hochleistungs-Faserlaser

Erben, BenjaminUntersuchungen zur Leistungs-kopplung von Hochleistungs-Diodenlasern mittels faserintegrier-ter Komponenten

Ewering, MaraProzessqualifizierung des Laserstrahllötens von Aluminium-Stahl-Verbindungen an Versuchs-karosserien

Fiedler, WolfgangProzesskontrolle beim Hochge-schwindigkeitsschweißen vondünnwandigen Aluminiumrohren

Fraas, ChristianEntwicklung und Evaluierung einesSensors zur optischen Messung derRelativgeschwindigkeit zwischenWerkstück und Bearbeitungskopfbei der Materialbearbeitung mitLaserstrahlung

Gehlen, Christoph DominicProzessdiagnostik laser-induzierterPlasmen beim präzisen Mikro-Materialabtrag mit Pulsgruppen

Grimm, StefanEntwicklung eines konfokalenLaserscanning Fluoreszenz-Endos-kops für die In-vivo-Tumordiagnostikim Gehirn

Gummersbach, MaxBeschichten dünner Bleche mit demMikro-Laserstrahl-Auftragschweißen

Hack, SebastianPolieren mit Laserstrahlung zurErzeugung von Design-Oberflächen

Hermes, ViktorDefektfreies Beschichten von y-TiAldurch Laserstrahl-Auftragschweißen

Hoeges, SimonModelltheoretische und experimen-telle Untersuchung der Dynamikkleiner Schmelzbäder

Kappler, JochenGrundlegende Untersuchungenzum Laserstrahl-Auftragschweißenvon Ti-6Al-4V mit Nd:YAG-Laser-strahlung

Leonhardt, JudithMessung der Lichtausbreitung in biologischem Gewebe und anGewebsphantomen (Bachelor Arbeit)

Masberg, Kai UllrichUntersuchung der Fügezone vonPreform und SLM-Bauteil aus demWerkstoff 1.2343

Pietrusky, MarcoLaserstrahl-Mikroschweißen mitFaserlaserstrahlung

Schloemer, PhilippAufbau und Entwicklung einerinversen Auflicht-Dunkelfeldoptikfür Streulichtmessungen an Protein-lösungen

Simon, OliverUntersuchung des Einflusses vonaktiv temperierten Optiken auf dieStrahlausbreitung von CO2-Hoch-leistungslasern

Vedder, ChristianBeitrag zur Verfahrensentwicklungdes Selektiven Reaktions-Lasersin-terns für die generative Herstellungvon Bauteilen aus Spinelkeramik

Waehler, TobiasLaserstrahlpolieren von schrägenEbenen und Nuten

Werner, MarcelUntersuchung alternativer Kühltech-niken für Hochleistungsdiodenlaser

Westphalen, ThomasUntersuchung von Hochleistungs-Diodenlaserbarren mittels Einzel-emitteraufgelöster Charakerisierung

Dissertations Diploma Theses



N. C. Stache, H. Zimmer, J. Gedicke, B. Regaard, A. Olowinsky, A. Knepper,T. AachApproaches for High-Speed MeltPool Detection in Laser WeldingApplicationsProceedings of VMV 20068 Seiten, 2006

Ü. Aydin, R. Noll, J. MakoweAutomatic sorting of aluminiumalloys by fast LIBS identification7th International Workshop Progress in Analytical Chemistry in the Steel and Metal Industries Ed. J. AngeliSeiten 309-314, 2006

D. PetringCombined cutting and welding:Laser beam quality enhancesprocess efficiency and flexibilityTagungsband-CD zum 2. Inter-nationalen Workshop »Faserlaser«in Dresden 34 Seiten, 2006

J. Gedicke, B. Regaard, K. Klages, A. Olowinsky, S. KaierleComparison of different processmonitoring methods for laserbeam micro weldingProceedings of ICALEO 258 Seiten, 2006

C. Scholz, K. Boucke, R. Poprawe, M. T. Kelemen, J. Weber, M. Mikulla,G. WeimannComparison between 50 W tapered laser arrays and taperedsingle emittersProceedings of SPIE 6104Seiten 61040G.1-61040G.8, 2006

C. Wessling, M. Traub, D. Hoffmann,R. PopraweDense wavelength multiplexing for high power diode laserProceedings of SPIE 6104Seiten 61040O.1-61040O.8, 2006

R. Liebers, U. Dürr, L. Trippe, W. SchulzDrilling Strategies for Metalswith Pulsed YAG-LasersProceedings of ICALEO 256 Seiten, 2006

K. Walther, M. Brajdic, E. W. KreutzEnhanced processing speed inlaser drilling of stainless steel by spatially and temporallysuperposed pulsed Nd:YAG laserradiationThe International Journal of Ad-vanced Manufacturing Technology5 Seiten, 2006

M. Leers, C. Scholz, K. Boucke, R. PopraweExpansion-matched passively-cooled heatsinks with low thermalresistance for high-power diodelaser barsProceedings of SPIE 6104Seiten 610403.1-610403.10, 2006

R. Wester, R. NollFast characterisation of steel Cleanness by Advanced Mathe-matical Analysis of Spark andLaser Source Optical EmissionData7th International Workshop Progress in Analytical Chemistry in the Steel and Metal Industries, Ed. J. AngeliSeiten 209-212, 2006

D. PetringFlexibles Laserschneiden und -schweißen von Blechbaugruppenohne WerkzeugwechselTagungsband-CD zum AachenerKolloquium für Lasertechnik AKL'06 22 Seiten, 2006

H. Bette, R. NollHigh-speed, high-resolution LIBSusing diode-pumped solid statelasersLaser-Induced Breakdown Spectroscopy (LIBS): Fundamentalsand ApplicationsSeiten 490-515, 2006

M. Traub, H.-D. Hoffmann, H.-D. Plum, K. Wieching, P. Loosen,R. PopraweHomogenization of high powerdiode laser beams for pumpingand direct applicationsProceedings of SPIE 6104Seiten 61040Q.1-61040Q.10, 2006

R. Noll, V. Sturm, M. Stepputat, A. Whitehouse, J. Young, P. EvansIndustrial applications of LIBS Laser-Induced Breakdown Spec-troscopy (LIBS): Fundamentals andApplicationsSeiten 400-439, 2006

J. Gedicke, B. Regaard, A. Gillner, S. KaierleKontrolle beim Mikroschweißen- Automatisierte Prozessüber-wachung durch koaxiale Prozesskontrolle mit Fremdbe-leuchtungLaser Technik Journal 45 Seiten , 2006

E. W. Kreutz, J. Willach, I. Kelbassa, S. Keutgen, R. PopraweLaser Technologies for Manufacturing and Repair of Rotating Machinery PowerPlant ComponentsProceedings of ISROMAC 8 Seiten, 2006

I. Kelbassa, A. Weisheit, K. Wissenbach, V. HermesLaser metal deposition of TiAl alloysProceedings of PICALO 25 Seiten, 2006

E. Haberstroh, W.-M. Hoffmann, R. Poprawe, F. SariLaser transmission joining in microtechnologyMicrosystem TechnologiesSeiten 632-639, 2006

A. Löbe, J. Vrenegor, R. Fleige, V. Sturm, R. NollLaser-induced ablation of a steelsample in different ambientgases by use of collinear multiplelaser pulsesAnalytical & Bioanalytical Chemistry Vol. 385, No. 2Seiten 326-332, 2006

R. Noll, U. PanneLaser-induced breakdown spectroscopy - EMSLIBS 2005Analytical & Bioanalytical Chemistry Vol. 385, No. 2Seiten 212-213, 2006

D. PetringLaserschneiden und -schweissenim fliegenden WechselTechnische Rundschau 16Seiten 38-41, 2006

D. PetringLasers in European AutomotiveManufacturing: HistoricalReview and Recent TrendsProceedings of ALAW 2006 16 Seiten, 2006

Scientific Publications


A. Gillner, K. Klages, F. SarıMikrofügen mit LaserstrahlungLaser Technik Journal 3Seiten 39-43, 2006

K. Nicklaus, M. Hoefer, D. Hoffmann, J. Luttmann, R. Wester, R. PopraweMOPA with kW average powerand multi MW peak power:experimental results, theoreticalmodeling and scaling limitsProceedings of SPIE 6100Seiten 610416.1-610416.11, 2006

J. Ilgner, M. Wehner, J. Lorenzen,M. Bovi, M. WesthofenMorphological effects of nano-second- and femtosecond-pulsedlaser ablation on human middleear ossiclesJournal of Biomedical Optics 11Seiten 41-47, 2006

H. Balzer, M. Höhne, R. Noll, V. SturmNew approach for online moni-toring of the Al depth profile of the hot-dip galvanised sheetsteel using LIBSAnalytical & Bioanalytical Chemistry Vol. 385, No. 2Seiten 225-233, 2006

T. Ebert, W. Meiners, M. PajunkNon corrosive micro coolers with matched CTEProceedings of SPIE 6104Seiten 01.1-01.7, 2006

H. Balzer, M. Hoehne, S. Hoelters,V. Sturm, R. Noll, E. Leunis, S. Janssen, M. Raulf, P. Sanchez, M. HemmerlinOnline depth profiling of zinccoated sheet steel by laser inducedbreakdown spectroscopy7th International Workshop Progress in Analytical Chemistry in the Steel and Metal Industries,Ed. J. AngeliSeiten 237-242, 2006

V. Sturm, A. Brysch, R. Noll, H. Brinkmann, R. Schwalbe, K. Mülheims, P. Luoto, P. Mannila,K. Heinänen, D. Carrascal, L. Sancho,A. Opfermann, K. Mavrommatis, H. W. Gudenau, A. Hatziapostolou, S. CourisOnline multi-element analysis of the top gas of a blast furnaceby LIBS7th International Workshop Progress in Analytical Chemistry in the Steel and Metal Industries,Ed. J. AngeliSeiten 183-188, 2006

K. Nicklaus, M. Daniels, R. Hohn, D. HoffmannOptical Isolator for UnpolarizedLaser Radiation at Multi-Kilo-watt Average PowerOSA - Technical Digest »Advanced Solid-State Photonics« 3 Seiten, 2006

I. Kelbassa, K. Walther, L. Trippe, W. Meiners, C. OverPotentials of manufacture and repair of nickel base turbine components used inaero engines and power plantsby laser metal deposition and laser drillingProceedings of ISJPPE 20259 Seiten, 2006

J. Vrenegor, V. Sturm, R. Noll, M. Hemmerlin, U. Thurmann, J. FlockPreparation and analysis of production control samples by a two-step laser method7th International Workshop Progress in Analytical Chemistry in the Steel and Metal Industries,Ed. J. AngeliSeiten 81-86, 2006

L. Trippe, K. Walther, E.W. Kreutz, R. PopraweProcess development and controlof laser drilled and shaped holesin turbine componentsProceedings of LAMP 5 Seiten, 2006

R. Poprawe, E. W. Kreutz, L. Trippe, K. WaltherProcess development for laserdrilled hole arrays in cooledstructuresTagungsband zum 3. Workshop des SFB 561Seiten 34-38, 2006

I. Kelbassa, C. Over, L. Trippe, E. W. Kreutz, K. WissenbachReconditioning of Nickel BaseHPT Blades and Vanes used inAero Engines and Power PlantGas Turbines by Combination of Direct Laser Forming, LaserMetal Deposition and Laser DrillingProceedings of PICALO 7 Seiten, 2006

B. Regaard, S. Kaierle, R. PopraweSelf guided laser weldingProceedings of ICALEO 257 Seiten , 2006

R. Noll, C. Fricke-BegemannStand-off Detection of SurfaceContaminations with Explosive Residues Using Laser-spectros-copic MethodsStand-off Detection of SuicideBombers and Mobile Subjects, Eds.: H. Schubert, A. Rimski-KorsakovSeiten 89-99, 2006

R. Wagner, J. Gottmann, A. Horn,E. W. KreutzSubwavelength ripple formationinduced by tightly focused femto-second laser radiationApplied Surface Science Vol. 252,Issue 24Seiten 8576-8579, 2006

H. Balzer, S. Hölters, V. Sturm, R. NollSystematic line selection for online coating thicknessmeasurement of galvanisedsheet steel using LIBS Analytical& Bioanalytical ChemistryVol. 385, No. 2Seiten 234-239, 2006

R. NollTerms and notations for laser-induced breakdown spectroscopyAnalytical & Bioanalytical ChemistryVol. 385, No. 2Seiten 214-218, 2006

J. Ilgner, M. Wehner, A. Donner,P. Düwel, R. Poprawe, M. Westhofen200 µm glass fibres for minimallyinvasive laser procedures inparanasal sinus surgeryMedical Laser Application 21Seiten 45-51, 2006

Scientific Publications


12.01.2006 - W. NeffLaserinduzierte MikroplasmenFachgespräch »Mikroplasmen«Begegnungszentrum Hof Beck-mann, Ruhr-Universität Bochum,Bochum

22.01.2006 - M. RoehnerCharacterization device for measuring beam parameter product and beam quality of collimated and uncollimateddiode lasersPhotonics West 2006, San Jose,CA, USA

23.01.2006 - R. NollLaser-Emissionsspektroskopie -Grundlagen, Grenzen und indus-trielle AnwendungspotentialeKolloquium, Fraunhofer-Institut fürZerstörungsfreie Prüfverfahren IZFP,Saarbrücken

23.01.2006 - M. LeersExpansion-matched passively-cooled heatsinks with low ther-mal resistance for high-powerdiode laser barsPhotonics West 2006, San Jose,CA, USA

23.01.2006 - C. ScholzComparison between 50 W tapered laser arrays and taperedsingle emittersPhotonics West 2006, San Jose,CA, USA

24.01.2006 - B. JungbluthHigh performance, widely tunable Ti:Sapphire laser, withnanosecond pulses Photonics West 2006, San Jose,CA, USA

24.01.2006 - P. RussbüldtGeneration of 13.5-fs pulsesfrom a diode-pumped Kerr-lensmode-locked prismless Cr:LiSGaFlaserPhotonics West 2006, San Jose,CA, USA

24.01.2006 - C. WesslingDense wavelength multiplexingfor a high power diode laserPhotonics West 2006, San Jose,CA, USA

24.01.2006 - M. TraubHomogenization of high powerdiode lasers for pumping anddirect applicationsPhotonics West 2006, San Jose,CA, USA

25.01.2006 - M. HoeferHigh power second and thirdharmonics generation of a twostage partially diode end-pumpedNd:YAG INNOSLAB MOPA SystemPhotonics West 2006, San Jose,CA, USA

25.01.2006 - K. NicklausMopa with kW average powerand multi MW peak power:experimental results theoreticalmodelling and scaling limits Photonics West 2006, San Jose,CA, USA

25.01.2006 - J. WüppenHigh efficient generation of tunable visible light by means of DFG in self-controlled con-version processesPhotonics West 2006, San Jose,CA, USA

26.01.2006 - J. GottmannSub-wavelength ripple forma-tion on dielectric and metallicmaterials induced by tightlyfocused femto-second laserradiation Photonics West 2006, San Jose,CA, USA

26.01.2006 - K. WissenbachLasereinsatz in der Oberflächen-behandlungMPA Darmstadt, Darmstadt

30.01.2006 - K. NicklausOptical isolator for unpolarizedlaser radiation at multi-kilowattaverage power ASSP 2006, Lake Tahoe, Nevada,USA

31.01.2006 - J. Loehring Thermal effects on the scalabilityof high power third harmonicgeneration at 355 nm in LBOASSP 2006, Lake Tahoe, Nevada,USA

08.02.2006 - T. Mans OptronikBundesagentur für AußenwirtschaftBFAI, Köln

24.02.2006 - R. PopraweCreation of the European Technology Platform »Photonics 21«, National LaserCenter, Pretoria, Südafrika

27.02.2006 - K. WaltherLaser technologies for manu-facturing and repair of rotatingmachinery power plant compo-nentsISROMAC-11, Honolulu, Hawaii,USA

06.03.2006 - H. BalzerOnline-Tiefenprofilanalyse verzinkter Stahlbleche mit Laser-Emissionsspektrometrie (LIBS)13. Anwendertreffen Röntgenflu-orezenz und Funkenemissionspek-trometrie, Steinfurt

06.03.2006 - G. OttoLasereinsatz in der Verpackungs-technikWorkshop »Easy Opening«, Fraun-hofer-Institut für Verfahrenstechniku. Verpackung IVV, Freising

06.03.2006 - E. W. KreutzBiologische Grundlagen und zulässige Grenzwerte zurKlassifizierungHochschulübergreifende Fortbildung,Universität Siegen

08.03.2006 - M. DahmenLaser materials processing - appli-cations, methods and systemsNational Laser Centre, Tshwane(Pretoria), Südafrika

09.03.2006 - G. OttoLaserverfahren für die Ver-packung medizintechnischerProdukte3. Duisburger Extrusionstagung,Universität Duisburg Gesamthoch-schule, Duisburg

11.03.2006 - R. NollNew frontiers for Laser-InducedBreakdown SpectroscopyPittcon 2006, 57th Pittsburgh Conference on Analytical Chemistryand Applied Spectroscopy, Invited Talk auf Symposium LIBS 21st Century, Orlando, FL, USA

11.03.2006 - E. W. KreutzPraktische Schutzmaßnahmenbei der LaseranwendungHaus der Technik, Essen

14.03.2006 - H.-D. HoffmannFestkörperlaser und Diodenlaserfür das Schweißen von Kunst-stoffenLaserschweißen von Kunststoffen,Süddeutsches Kunststoffzentrum -Kunststoff, Forschung und Entwick-lung, SKZ-KFE GmbH, Würzburg

15.03.2006 - E. W. KreutzLasersicherheit - was ist wirklichwichtig?Süddeutsches Kunststoffzentrum,Würzburg

15.03.2006 - K. WaltherProcess development for laserdrilled hole arrays in cooledstructuresWorkshop SFB561, Aachen

27.03.2006 - U. EppeltMicroprocessing, from nano to femto14th Annual Automotive LaserApplications Workshop ALAW2006, Plymouth, MI, USA

27.03.2006 - C. A. HartmannUntersuchung zum Abtrag vonMetallen mit Pikosekunden undNanosekunden MehrfachpulsenDPG-Frühjahrstagung, UniversitätAugsburg, Institut für Physik, Augsburg

27.03.2006 - A. HornAusgewählte Anwendungen der Wechselwirkung von Femtosekunden Laserstrahlungmit MaterieDPG-Frühjahrstagung, UniversitätAugsburg, Institut für Physik, Augsburg

27.03.2006 - I. Mingareev Prozessvisualisierung bei derMaterialbearbeitung mit ultra-kurzen Laserpulsen mittelsPump&Probe-PhotographieDPG-Frühjahrstagung, UniversitätAugsburg, Institut für Physik, Augsburg

28.03.2006 - A. GillnerGroßflächenabtrag mit KurzpulslaserstrahlquellenDPG-Frühjahrstagung, UniversitätAugsburg, Institut für Physik, Augsburg

Lectures

28.03.2006 - D. PetringCombined cutting and weldingFraunhofer Pre-Conference ofALAW 2006, Plymouth, MI, USA

28.03.2006 - R. PopraweNew lasers for new applicationsFraunhofer Pre-Conference ofALAW 2006, Plymouth, MI, USA

29.03.2006 - E. W. KreutzProcess development and control of melt dominated laserdrillingDPG-Frühjahrstagung, UniversitätAugsburg, Institut für Physik, Augsburg

30.03.2006 - D. PetringLasers in European automotivemanufacturing: Historical reviewand recent trends14th Annual Automotive LaserApplications Workshop ALAW2006, Plymouth, MI, USA

30.03.2006 - M. RammeDoppelpulseDPG-Frühjahrstagung, UniversitätAugsburg, Institut für Physik, Augsburg

03.04.2006 - R. Poprawe Holistic development of high power laser sources andcorresponding applicationsPICALO 2006, Melbourne, Australien

05.04.2006 - I. KelbassaComparison of Ti-6246 BLISK blade repair methods on bladereplacement via repair by laserwelding and reconditioning of local damages by laser depo-sitionPICALO 2006, Melbourne, Australien

05.04.2006 - I. KelbassaReconditioning of Nickel baseHPT blades and vanes used inaero engines and power plantgas turbines by combination ofdirect laser forming, laser metaldeposition and laser drillingPICALO 2006, Melbourne, Australien

05.04.2006 - I. KelbassaLaser metal deposition of TiAl alloysPICALO 2006, Melbourne, Australien

12.04.2006 - A. L. BogleaInnovative laser based pick-and-join tool for micro-assemblyMarie Curie Conference MC2,»Putting the Knowledge-basedSociety into Practice«, University ofManchester, Manchester, UK

24.04.2006 - E. Bremus-KöberlingNeuron-material interactions on surfaces with complex topo-graphies (Poster)2006 Regenerate - World Congresson Tissue Engineering and Regene-rative Medicine, Pittsburgh, PA, USA

03.05.2006 - S. KaierleWie funktionieren die Laserbearbeitungsverfahren? Aachener Kolloquium für Laser-technik AKL’06, Aachen

04.05.2006 - A. GillnerKombilas - Laserpräzisionsabtragvon KeramikwerkstoffenAachener Kolloquium für Laser-technik AKL’06, Aachen

04.05.2006 - R. Poprawe Trends und Perspektiven derLasertechnik Aachener Kolloquium für Laser-technik AKL’06, Aachen

04.05.2006 - W. MeinersSchnelle Herstellung von Bauteilen mit Mikrostrukturenmit dem SLM-VerfahrenAachener Kolloquium für Laser-technik AKL'06, Aachen

05.05.2006 - D. PetringFlexibles Laserschneiden und -schweißen von Blechbaugruppenohne WerkzeugwechselAachener Kolloquium für Laser-technik AKL’06, Aachen

05.05.2006 - R. NollLaser-Direktanalyse von Prozess-kontroll- und Schlackeproben in der SekundärmetallurgieAusschusssitzung »MetallurgischeGrundlagen«, Stahlinstitut VDEh,Düsseldorf

07.05.2006 - I. Mingareev Extension of the process limits in material processing with femtosecond laser radiation by means of high-speed pump-probe photographySPIE High Power Laser Ablation2006, Sagebrush Inn & ConferenceCenter, Taos, NM, USA

09.05.2006 - R. Poprawe Neue Trends in der Lasertechnik- Chancen und Märkte für Inves-torenInvestmentforum, München

15.05.2006 - K. WissenbachPotentials of highly-developedlaser base techniques for additivemanufacturing and repair ofcomplex shaped aero engineparts out of nickel and titaniumbase alloysASM Konferenz, Seattle, WA, USA

16.05.2006 - E. W. KreutzLasersicherheitBG Feinmechanik & Elektrotechnik,Bad Münstereifel

16.05.2006 - R. WesterFast characterisation of steel cleanness by advanced mathe-matical analysis of spark andlaser source optical emission dataCETAS2006, 7th InternationalWorkshop on Progress in AnalyticalChemistry in the Steel and MetalIndustries, Luxemburg, Luxemburg

16.05.2006 - Ü. AydinAutomatic sorting of aluminiumalloys by fast LIBS identificationCETAS 2006, 7th InternationalWorkshop on Progress in AnalyticalChemistry in the Steel and MetalIndustries, Luxemburg, Luxemburg

16.05.2006 - H. BalzerOnline depth profiling of zinccoated sheet steel by Laser-In-duced Breakdown SpectroscopyCETAS 2006, 7th InternationalWorkshop on Progress in AnalyticalChemistry in the Steel and MetalIndustries, Luxemburg, Luxemburg

16.05.2006 - V. SturmOnline multi-element analysis of the top gas of a blast furnaceby LIBSCETAS 2006, 7th InternationalWorkshop on Progress in AnalyticalChemistry in the Steel and MetalIndustries, Luxemburg, Luxemburg

16.05.2006 - J. VrenegorPreparation and analysis of production control samples by a two-step laser methodCETAS 2006, 7th InternationalWorkshop on Progress in AnalyticalChemistry in the Steel and MetalIndustries, Luxemburg, Luxemburg

17.05.2006 - A. HornDiagnostics of laser-inducedmelting of matter by ultra-fastmetrologyLAMP 2006, Kyoto Research Park,Kyoto, Japan

17.05.2006 - C. A. HartmannInvestigation on laser microablation of steel using short and ultrashort IR multipulsesLAMP 2006, Kyoto Research Park,Kyoto, Japan

17.05.2006 - J. GottmannInvestigation of ripples with sub-wavelength periodicity inducedby tightly focused femtosecondlaser radiation on various mate-rialsLAMP 2006, Kyoto Research Park,Kyoto, Japan

18.05.2006 - D. WortmannRefractive index modification infused silica with fs-double-pulsesLAMP 2006, Kyoto Research Park,Kyoto, Japan

19.05.2006 - R. PoprawePerspectives of laser processingand new applicationsLAMP 2006, Kyoto Research Park,Kyoto, Japan

28.05.2006 - C. JohnigkReinigen und Vorbehandeln mit LaserstrahlungOTTI-Profiforum »Reinigen und Vor-behandeln vor der Beschichtung«,OTTI Kolleg e.V., Regensburg

28.05.2006 - A. L. BogleaAdvanced laser based tools formicro-assemblyPoduktionstechnik Seminar, Tech-nical University Cluj-Napoca, Facultyof machine, Cluj-Napoca, Rumänien

31.05.2006 - K. WissenbachLasereinsatz in der Oberflächen-technik - Ein ÜberblickAachener Laserseminar »Vorsprungdurch Laser-Oberflächentechnik -Auftragschweißen, Reparieren, Reini-gen, Polieren«, Fraunhofer-Institutfür Lasertechnik ILT, Aachen

31.05.2006 - C. JonhnigkReinigen mit LaserstrahlungAachener Laserseminar »Vorsprungdurch Laser-Oberflächentechnik -Auftragschweißen, Reparieren, Reini-gen, Polieren«, Fraunhofer-Institutfür Lasertechnik ILT, Aachen


Lectures

31.05.2006 - E. WillenborgPolieren mit LaserstrahlungAachener Laserseminar »Vorsprungdurch Laser-Oberflächentechnik -Auftragschweißen, Reparieren, Reini-gen, Polieren«, Fraunhofer-Institutfür Lasertechnik ILT, Aachen

31.05.2006 - K. WissenbachStrukturieren mit LaserstrahlungAachener Laserseminar »Vorsprungdurch Laser-Oberflächentechnik -Auftragschweißen, Reparieren, Reini-gen, Polieren«, Fraunhofer-Institutfür Lasertechnik ILT, Aachen

31.05.2006 - G. VitrRandschichthärten und Wärmebehandeln von Stählenmit Laserstrahlung Aachener Laserseminar »Vorsprungdurch Laser-Oberflächentechnik -Auftragschweißen, Reparieren, Reini-gen, Polieren«, Fraunhofer-Institutfür Lasertechnik ILT, Aachen

31.05.2006 - A. WeisheitLaserstrahl-Auftragschweißenvon Funktionsschichten für denVerschleiß- und KorrosionsschutzAachener Laserseminar »Vorsprungdurch Laser-Oberflächentechnik -Auftragschweißen, Reparieren, Reini-gen, Polieren«, Fraunhofer-Institutfür Lasertechnik ILT, Aachen

31.05.2006 - A. GasserAnlagen-Systemtechnik für dieLaseroberflächentechnikAachener Laserseminar »Vorsprungdurch Laser-Oberflächentechnik -Auftragschweißen, Reparieren, Reini-gen, Polieren«, Fraunhofer-Institutfür Lasertechnik ILT, Aachen

06.06.2006 - T. MansOptische Technologien - Zukunftund TechnikKonferenz Zukunft und Technik,Dormagen

13.06.2006 - R. NollOnline depth profiling of zinccoated sheet steel by Laser-Indu-ced Breakdown SpectroscopyTGS9, ECSC Meeting, Rotherham,UK

16.06.2006 - W. MeinersManufacturing of individualbone implants using selectivelaser melting2. Bernd-Spiessl-Symposium 2006,Basel, Schweiz

16.06.2006 - S. AbedManufacture of injection mouldsout of standard tool steel usingdirect laser forming10th International Pattern ModelMaking Congress, Maison de laMécanique, UFIMO (Union Françaisedes Industries de Mise en Formedes Métaux et Outillage), Paris,Frankreich

21.06.2006 - M. WehnerSingle cell optoporation for uptake of extracellular substances (Poster) Jahrestagung »Mikrosysteme fürdie Biotechnologie«, Fraunhofer-Institut für Fertigungstechnik undangewandte MaterialforschungIFAM, Bremen

21.06.2006 - M. WehnerRapid prototyping of microfluidicdevices in polymers (Poster)Jahrestagung »Mikrosysteme fürdie Biotechnologie«, Fraunhofer-Institut für Fertigungstechnik undangewandte MaterialforschungIFAM, Bremen

22.06.2006 - G. BackesLaserbearbeitung bei TriebwerkenBundesakademie für Wehrverwal-tung und Wehrtechnik, Mannheim

22.06.2006 - S. AbedFabrication directe d’outillagesd’injection en aciers outil stan-dard et de pièces techniques en alliages d’Aluminium et deTitane par fusion laser de poudreJournée technique, Université deTechnologie de Belfort-Montbéliard,Site de Sevenan, Belfort, Frankreich

27.06.2006 - H.-D. HoffmannHigh-power solid-state slab-lasers and nonlinear frequencyconversionLaser Optic Conference, A. F. IoffePhysical-Technical Institute, St. Petersburg, Russland

28.06.2006 - F. SchmittVergleich des Perkussions- und Wendelbohrens mit Kurz-pulslasernWLT-Summerschool, LZH Laser Akademie, Hannover

28.06.2006 - Ü. AydinHigh speed identification ofaluminium alloys by Laser-InducedBreakdown Spectroscopy formaterial recyclingLZH Laser Zentrum Hannover e.V.,Hannover

28.06.2006 - C. D. GehlenOrtsaufgelöste Untersuchunglaserinduzierter Plasmen beimpräzisen Mikro-Materialabtragmit PulsgruppenLZH Laser Zentrum Hannover e.V.,Hannover

04.07.2006 - E. W. KreutzLaser in der Materialbearbeitungund andere als optische undelektrische GefahrenTA Esslingen, Ostfildern

06.07.2006 - E. W. KreutzGefährdungen von Augen undHaut durch LaserstrahlungBG Metall-Süd, Markt Triefenstein-Lengfurt

06.07.2006 - M. LeersStress reduced packagingBright-EU Workshop, University of Cambridge, Cambridge, UK

06.07.2006 - D. PetringKombiniertes Schneiden undSchweißen: Laserstrahlqualitätsteigert Prozesseffizienz und -flexibilität2. Internationaler Workshop Faserlaser, Dresden

13.07.2006 - R. PopraweLasertechnik: Wie aus TechnikUnternehmen werdenBusiness Angels Veranstaltung,Aachen

17.07.2006 - S. KaierleLaser aided manufacturing in Germany and EuropeGARELAM, National Academy of Science, Washington, USA

18.07.2006 - E. W. KreutzEinrichten von Laserbereichenund andere als optische Gefahren-potenzialeBG Metall-Süd, Markt Triefenstein-Lengfurt

03.09.2006 - R. PopraweThe future of high power lasertechniquesXVI. International Symposium GCL/HPL 2006, Gmunden, Österreich

03.09.2006 - R. NollApplications of LIBSLIBS 2006, 4th International Confe-rence on Laser-Induced BreakdownSpectroscopy and Applications,Montreal, Kanada

05.09.2006 - R. NollTeleLis - Remote LIBS measure-ments with double pulsesLIBS 2006, 4th International Confe-rence on Laser-Induced BreakdownSpectroscopy and Applications,Montreal, Kanada

05.09.2006 - R. NollHigh-speed LIBS with low energymultiple pulses for online moni-toring of thickness and depthprofile of galvanised sheet steelLIBS 2006, 4th International Confe-rence on Laser-Induced BreakdownSpectroscopy and Applications,Montreal, Kanada

06.09.2006 - R. NollStandardization of LIBSLIBS 2006, 4th International Confe-rence on Laser-Induced BreakdownSpectroscopy and Applications,Montreal, Kanada

13.09.2006 - W. WawersLaser drilling with helical drillingoptics1. Internationales Symposium für das Laser-Micromachining,Chemnitz

13.09.2006 - A. GillnerLaserstrahlmikroschweißen mitFaserlasern und innovativen Ver-fahrenskonzeptenLaser-Anwender-Forum, BIAS, Bremen

20.09.2006 - A. GasserAplicaciones industriales de lasoldadura de aporte con láserJornada de Difusion Technológica,Lortek, Ordizia, Spanien

24.09.2006 - S. KaierleLaser materials processing: appli-cations, methods and systems Fachmesse INSITE, Johannesburg,Südafrika


Lectures


Lectures

25.09.2006 - N. PirchMechanisms of surface ripplingduring laser polishing 8th International Seminar »Nu-merical Analysis of Weldability«,Graz-Seggau, Östereich

27.09.2006 - N. PirchCalculations of stresses duringlaser welding, shortcomings of finite element approximation8th International Seminar »Nu-merical Analysis of Weldability«,Graz-Seggau, Östereich

04.10.2006 - J. HoltkampLaser assisted forming: process & toolsMasmicro Demonstration Day,Stuttgart

11.10.2006 - P. AbelsQuality control in laser materialsprocessing - essentials and indu-strial applicationILAS Konferencia 2006, Bay ZoltánInstitute for Materials Science andTechnology, Budapest, Ungarn

11.10.2006 - E. Bremus-Köberling Neurite growth on micro-patterned surfaces with complextopographies (Poster)2006 Annual Fall Meeting, Biome-dical Engineering Society (BMES),Chicago, IL, USA

15.10.2006 - K. BergmannCharacterization of grazing incidence collectors under nearproduction conditions (Poster)EUVL Symposium 2006, InternationalSymposium on Extreme UltravioletLithography, Barcelona, Spanien

15.10.2006 - L. JuschkinEUV microscopy for defect inspection (Poster)EUVL Symposium 2006, InternationalSymposium on Extreme UltravioletLithography, Barcelona, Spanien

16.10.2006 - K. BergmannTest stand for optical characte-rization of grazing incidencecollectors (Poster)EUVL Symposium 2006, InternationalSymposium on Extreme UltravioletLithography, Barcelona, Spanien

18.10.2006 - S. KaierleQualitätssicherung in der Laserbearbeitung durch optischeSchweißnahtüberwachungFachtagung Optische Industrie-sensorik, Böblingen

20.10.2006 - S. KaierleQualitätssicherung beim Lötenmit LaserstrahlungGFaI Jahresversammlung, Gesell-schaft zur Förderung angewandterInformatik e.V. (GFaI), Berlin

27.10.2006 - A. GillnerLasergestütztes Gewebeklebenfür Anastomosen und zum naht-freien Wundverschluss LIME Erlangen, BLZ – BayerischesLaserzentrum GmbH, Erlangen

31.10.2006 - A. L. BogleaFiber laser pick-and-join tool for welding of thermoplasticsICALEO® 2006, Scottsdale, Arizona, USA

31.10.2006 - B. RegaardSelf guided laser weldingICALEO® 2006, Scottsdale, Arizona, USA

01.11.2006 - A. OlowinskySHADOW® - new applications in electronics and micromecanicsICALEO® 2006, Scottsdale, Arizona, USA

01.11.2006 - J. GedickeComparison of different processmonitoring methods for laserbeam micro weldingICALEO® 2006, Scottsdale, Arizona, USA

02.11.2006 - E. WillenborgAutomatisches Polieren von Umformwerkzeugen derKaltmassivumformungWorkshop Polieren mit dem Laser,GCFG, Hagen

07.11.2006 - M. TraubProzessangepasste Formung und Homogenisierung vonDiodenlaserstrahlungIWS Workshop Diodenlaser,Fraunhofer-Institut für Werkstoff-und Strahltechnik IWS, Dresden

07.11.2006 - C. WesslingFasergekoppelte Diodenlaser-systeme hoher BrillanzIWS Workshop Diodenlaser, Fraunhofer-Institut für Werkstoff-und Strahltechnik IWS, Dresden

08.11.2006 - R. NollIndustrielle Anwendungen derLaser-DirektanalyseJahrestagung GDMB, Goslar

09.11.2006 - S. KaierleIndustrielle Anwendungen brillianter Diodenlaser beimAluminiumschweißen, Härtenund BeschichtenIWS Workshop Diodenlaser, Fraunhofer-Institut für Werkstoff-und Strahltechnik IWS, Dresden

16.11.2006 - D. PetringFlexibles Schneiden undSchweißen in der Blechverarbei-tung mit dem Laser-KombikopfFertigungstechnisches Kolloquiumder ETH Zürich, IWF Institut fürWerkzeugmaschinen und Fertigung,Zürich, Schweiz

20.11.2006 - S. KaierleProzessüberwachung für dieMaterialbearbeitung mit Laser-strahlung - Grundlagen undAnwendungsgebieteAachener Laserseminar »OnlineQualitätssicherung in der Laserfüge-technik - Sicheres und effizientesLaserstrahlschweißen«, Fraunhofer ILT, Aachen

20.11.2006 - S. MannProzessüberwachung mit koaxialer FremdbeleuchtungAachener Laserseminar »OnlineQualitätssicherung in der Laserfüge-technik - Sicheres und effizientesLaserstrahlschweißen«, Fraunhofer ILT, Aachen

20.11.2006 - A. GillnerMicro and nanofunctionalization of surfacesNanofair Karlsruhe, KongresszentrumKarlsruhe, Karlsruhe

21.11.2006 - S. KaierleNahtfolge und Nahtinspektion -Grundlagen und Anwendungs-beispieleAachener Laserseminar »OnlineQualitätssicherung in der Laserfüge-technik - Sicheres und effizientesLaserstrahlschweißen«, Fraunhofer ILT, Aachen

21.11.2006 - B. RegaardAutonome NahtfolgeAachener Laserseminar »OnlineQualitätssicherung in der Laserfüge-technik - Sicheres und effizientesLaserstrahlschweißen«, Fraunhofer ILT, Aachen

22.11.2006 - D. PetringLaserstrahlschneiden und -schweißen: Grundlagen für dieAnwendungAachener Laserseminar »InnovativeLaserschneid- und Laserschweiß-prozesse«, Fraunhofer ILT, Aachen

22.11.2006 - D. PetringLaserhybridschweißen: Stand derTechnik und aktuelle FortschritteAachener Laserseminar »InnovativeLaserschneid- und Laserschweiß-prozesse«, Fraunhofer ILT, Aachen

22.11.2006 - F. SchneiderFlexible Fertigung von Blechbau-gruppen: effizient Laserstrahl-schweißen und -schneiden mitdem KombikopfAachener Laserseminar »InnovativeLaserschneid- und Laserschweiß-prozesse«, Fraunhofer ILT, Aachen

22.11.2006 - G. OttoProzesslösungen zum Laser-trennen von Leiterplatten mitMaterialstärke >1 mmLaser-Workshop, Gas AutomationGmbH, St. Georgen (Schwarzwald)

23.11.2006 - R. NollGrundlagen und Methoden der Lasermesstechnik - Stand derTechnik und neue EntwicklungenAachener Laserseminar »Lasermess-technik für die metallverarbeitendeIndustrie«, Fraunhofer ILT, Aachen


23.11.2006 - A. LamottOnline-Überwachung vonSchweißprozessen mit Emissions-spektrometrieAachener Laserseminar »Lasermess-technik für die metallverarbeitendeIndustrie«, Fraunhofer ILT, Aachen

27.11.2006 - J. WilkesRapid manufacturing of ceramiccomponents for medical andtechnical applications via selec-tive laser meltingEuro-uRapid, Frankfurt am Main

30.11.2006 - W. MeinersVorsprung im Werkzeugbaudurch innovative LasertechnikEuromold 2006, Fachforum Werkzeug und Formenbau, Frankfurt am Main

05.12.2006 - E. W. KreutzTechnische, organisatorische undpersönliche Schutzmaßnahmenbei der Materialbearbeitung mitLaserstrahlungBG Feinmechanik & Elektrotechnik,Dresden

06.12.2006 - R. PoprawePhotonics21 - Die neue EU TechnologieplattformWissenschaftliches Forum, Ulm

08.12.2006 - R. NollPhysik - Aufgabe und BerufPius Gymnasium, Aachen

08.12.2006 - S. PfeifferStrukturelle Stabilität vonModellen zur Schweißverzugs-simulation von StahlwerkstoffenFOSTA-Arbeitskreis Schweißverzug,zwb München

12.12.2006 - K. WissenbachLaser surface treatmentShort course on »Material Processing by Laser«, AIDO, Paterna, Spanien

13.12.2006 - S. AbedFabrication rapide de piècesmétalliques et d‘outillages parfusion laser 5eme Journée Technique FabricationRapide: réalité ou utopie? Tendance du marché et enjeux futurs Pôle Européen de Plasturgie, Oyonnax, Frankreich

12.01.2006Chair for Laser Technology LLTat RWTH AachenLecture in association with theRWTH Colloquium on LaserTechnologyProf. Wolfgang Kowalsky, TechnischeUniversität Braunschweig, Institutfür Hochfrequenztechnik »Organische Leuchtdioden undLaser«

21.02.2006, AachenUnihits for KidsForum organized by the Chair for Laser Technology LLT and theFraunhofer ILT to give advice onscientific careers to students at theGesamtschule Langerwehe.

03.03.2006, Aachen22nd seminar of the »Aix LaserPeople«the alumni club of the FraunhoferILT and the Chair for Laser Techno-logy LLT, featuring lectures by Dr. Stefan Kaierle, Fraunhofer ILT,on »New developments in systemsengineering at the Fraunhofer ILT«and Dr. Detlef Becker, VorwerkElektrowerke GmbH, Wuppertal, onthe topic of »Quality managementin the procurement of engineeringproducts«. The lectures were followedby a visit to the premises of FEVMotorentechnik GmbH in Aachen.

Lectures Conventions and Conferences

Above: Opening of the schoolsevent »The Fascination of Light«on May 2, 2006, at the LudwigForum for International Art inAachen.Middle: Federal minister Dr. Annette Schavan at the science forum in Ulm.Below: Presentation of certificateto the Fraunhofer ILT on May 2,2006, in Aachen, confirming its selection as a »landmark« in the»Land of Ideas«.

28.03.2006Plymouth, Michigan, USA»Open house CLT«The Fraunhofer CLT held an openday on March 28, 2006, as part ofthe Automotive Laser ApplicationsWorkshop ALAW. Over 100 visitorsattended presentations on Fraunho-fer laser activities in Germany andthe USA. Lectures were given onlaser materials processing on themicro and macro scales, and on thelatest developments in componentsand laser resonators. The results ofvarious research projects were pre-sented: laser welding with high-power fiber lasers, integrated lasercutting and welding with the combihead, robot-assisted remote weld-ing, micromaterials processing inconnection with drilling and joining,and surface processing techniquessuch as coating and cleaning. Thecomponents and systems demons-trated to visitors ranged from scan-ners for 10-kW fiber lasers withautonomous position recording,fiber lasers with flexible pulse para-meters and extremely high-brilliancediode lasers (75 W output from a100-µm fiber) to complete customer-specific systems for manufacturinguse.

20.04.2006Chair for Laser Technology LLTat RWTH AachenLecture in association with the RWTH Colloquium on LaserTechnologyDr. Martin Straub, Lehrstuhl fürLasertechnik, RWTH Aachen»Femtosecond-fabrication and ana-lysis of micro- and nanostructures«

26.04.2006Chair for Laser Technology LLTat RWTH AachenLecture in association with the RWTH Colloquium on LaserTechnologyProf. Klaus M. Radermacher, Lehrstuhl für Medizintechnik,RWTH Aachen»Computergestützte Chirurgie –Stand der Technik und Trends«

02. - 05.05.2006, AachenSchools event»The Fascination of Light«From May 2 to 5, 2006, over 400school students aged 14-18 had achance to learn more about opticaltechnologies during an event bear-ing the slogan »The Fascination ofLight«. This outreach event inconnection with the 6th Aachen

Colloquium for Laser TechnologyAKL´06 (www.ilt.fraunhofer.de/akl06)enabled tomorrow’s university stu-dents to get to know this expand-ing sector of industry. Expertly prepared learning activities and presentations fired the youngsters’enthusiasm. Careers advisors wereon hand to provide details of thejob opportunities available in thissector of industry.

To conduct this schools event, theFraunhofer ILT arranged for theBMBF-sponsored travelling exhibition»The Fascination of Light« to beinstalled at the Ludwig Forum for International Art. An area ofapprox. 250 m2 was filled withhands-on exhibits and accompany-ing explanatory material. Researchstaff from the Fraunhofer ILT andstudents from the Chair for LaserTechnology LLT at RWTH AachenUniversity looked after the visitingschool groups at the Ludwig Forumduring the four days of the event.The students were also introducedto the significance of light as anartistic medium. For this part oftheir visit, the students were guidedby the specialist teachers of theLudwig Forum’s permanent muse-um staff.

The Fraunhofer ILT’s schools eventat the Ludwig Forum was alsoincorporated in a one-day eventdevoted to optical technologiesheld on May 2 in Aachen as part ofthe initiative »Zukunft durch Inno-vation.NRW« organized by theLand of North Rhine-Westphalia.This event was supported by smalland medium-sized enterprises(SMEs) in addition to the participat-ing universities and research insti-tutions. Interested school studentswere able to take part in a choiceof 15 workshops and visits to com-panies, allowing them to obtain areal-life view of the world of opticaltechnologies. A varied selection oftopics including laser technology,lighting systems for cars, and medi-cal engineering, enabled the stu-dents to awaken previously undis-covered skills and talents, and toreinforce existing interests with aview to future professional trainingand career options.

The Fraunhofer ILT schools eventwas moreover tied in with thenationwide initiative »Germany -Land of Ideas«, under the patro-nage of German president Horst

Köhler (see also www.land-der-ideen.de). The Fraunhofer ILT wasone of the 365 successful appli-cants out of a total of 1200 to beselected as a »landmark« in theLand of Ideas. The certificate awar-ded in connection with this honorwas officially presented to theFraunhofer ILT on May 2 during a press conference at the LudwigForum in Aachen.

03. - 05.05.2006, Aachen6th Aachen Colloquium for Laser Technology AKL’06The Aachen Colloquium for LaserTechnology AKL is the industry’s keyforum for applied laser technology.This year about 430 participants,including representatives of nume-rous laser manufacturers and usersof laser technology, gathered inAachen to discuss success stories,potential applications and recentdevelopments in the field of lasertechnology. Using examples frompractical industrial applications andinnovative R&D projects, a total of32 technical lectures illustrated theprospects of laser technology for awide variety of applications in suchdiverse industries as automobilemanufacturing, metal processing,tool and die making, optical, elec-trical and electronic engineering.Non-financial sponsors of the con-ference included the Association ofGerman Engineers (VDI), the Ger-man Association of AutomobileManufacturers (VDA), the GermanEngineering Federation (VDMA)and the German Association ofOptical, Medical and MechatronicsManufacturers (SPECTARIS).

In addition to lectures held by laserexperts from industrial companiesand research establishments, morethan 60 demonstrations of future-oriented laser technology applica-tions were carried out at the Fraun-hofer ILT and by companies fromthe Laser Application Center to illus-trate state-of-the-art systems andprocesses. An exhibition area with34 exhibitors provided an ideal sett-ing for the exchange of informationand professional opinions.

A new feature of AKL´06 was theextremely well-attended beginners’seminar on laser technology, heldon May 3, 2006. This seminar spe-cifically targeted companies thathad not dealt with laser technologybefore - neither as vendors nor asusers.


Above: School students discovering»The Fascination of Light« on May 2,2006, at the Ludwig Forum for Inter-national Art in Aachen.Middle and below: School studentstaking part in the initiative »Zukunftdurch Innovation«.

Conventions and Conferences

Novices to the laser world wereable to learn in a clearly structuredformat how laser machining pro-cesses work, what type of laser isemployed for different applications,which areas of industry employlaser technology, how to determinewhen laser processing is a worth-while option, what services areoffered by laser subcontractingfirms, and what trends and prospectsare in view for various aspects oflaser technology. The complete pro-gram, including demonstrations atthe Fraunhofer ILT, can be found onthe ILT Web site at www.ilt.fraun-hofer.de/AKL06.

The AKL’06 conference proceedingsand the beginners’ seminar on lasertechnology, including 2 CD-ROMscontaining the full set of lecture slides, can be ordered from thepublisher, VDI Verlag GmbH, at the following Internet address:www.vdi-nachrichten.com/buchshop(search key: AKL).

03.05.2006, AachenTechnology Business Day TBTTo complement the specialist tech-nical conference at AKL’06, entre-preneurs and business executiveswere given an opportunity to gatheran overview of current markettrends in laser technology, automanufacturing and machine tools.The Technology Business Day thattook place on May 3, 2006, focusedon non-technical content, taking in such subjects as financing, legalaspects, human resources, market-ing, distribution, and strategy, in a series of 13 lectures. The full pro-gram can be found on the Fraun-hofer ILT Web site at www.ilt.fraun-hofer.de/TBT06.

The TBT’06 proceedings including aCD-ROM containing the speakers’lecture slides, can be obtained fromthe customer service department of the WirtschaftsWoche magazineat the following Internet address:www.wiwo-shop.de.

03. and 04.05.2006, AachenPresentation of the 2006 Laser-technik innovation and early-stage research prizesThe Lasertechnik innovation prizeawarded by the association Arbeits-kreis Lasertechnik e. V. was presen-ted to the winners in a ceremony at the Aula Carolina zu Aachen onMay 4, 2006, during the Aachen

Colloquium for Laser TechnologyAKL´06. Two outstanding engineersreceived prizes in 2006: ProfessorDr.-Ing. Horst Exner - professor ofphysical engineering/laser engineer-ing at Mittweida University ofApplied Sciences and director ofLaserinstitut Mittelsachsen e. V. -for the development of laser micro-sintering, and Dipl.-Ing. StefanWischmann - head of beam andsensor technology in the Sales/Engineering department of the AutoDivision of ThyssenKrupp Steel AG,Duisburg - for the development of an optical system for laser-beamwelding with integrated weld follow-ing for butt and fillet welds.

The prizes, each worth 3000 euros,were presented to the two winnersby Professor Dr. rer. nat. ReinhartPoprawe M.A. - deputy chairman ofArbeitskreis Lasertechnik e.V. anddirector of the Fraunhofer Institutefor Laser Technology ILT, Aachen –and by Dr. Bernd Schulte - presidentof the European Photonics IndustryConsortium EPIC, vice-president ofthe European Technology Platformfor optical technologies Photonics21,and executive vice-president, COOof Aixtron AG, Aachen.

At the opening of AKL´06 one dayearlier, on May 3, 2006, the Laser-technik early-stage research prizewas presented at a ceremony in theLudwig Forum Aachen to Dr.-Ing.Dipl.-Wirt. Ing. Karsten Schneefuß - assistant to the director of theelectronics division of Hella KGaAHueck & Co., Lippstadt - for thedevelopment of a hybrid test systemfor in-situ form and roughnessmeasurement of microstructuredoptical functional surfaces, whileworking on his doctoral thesis atthe Chair of Metrology and QualityManagement at RWTH Aachen University.

The Lasertechnik innovation prize isawarded at 2-yearly intervals by theassociation Arbeitskreis Lasertech-nik e. V., Aachen, to two selectedindividuals whose exceptional skillsand dedicated work have led toinnovations in laser technology.Through the award of this prize, aspotlight is focused on the interfacebetween scientific research andindustrial practice. Given the intrinsicdifferences between these twoareas of activity, applications for theinnovation prize are judged in two

separate categories: »industrialpractice« and »applied research«.The prize-winners are selected andnominated on the basis of the sub-mitted applications by the executivecommittee and members of theassociation Arbeitskreis Lasertech-nik e. V.

The Lasertechnik early-stage re-search prize is a new prize, awardedfor the first time in 2006 by theassociation Arbeitskreis Lasertechnike. V., with the aim of supportingresearch in the field of laser techno-logy at RWTH Aachen University byscientists at an early stage of theircareers. This prize is awarded toholders of a doctorate from RWTHAachen University, whose publisheddoctoral thesis and accompanyingproject work represent a significantcontribution to the advancement ofapplication-oriented laser technolo-gy, and at the same time promise to be of considerable utility valueto industry.

Further information on the prize-winners can be found on the Website of the association ArbeitskreisLasertechnik e. V. at www.akl-ev.de.

05.05.2006, Aachen23rd seminar of the »Aix LaserPeople«the alumni club of the FraunhoferILT and the Chair for Laser Techno-logy LLT, including an opportunityto watch over 60 live demonstrationsin the ILT Laser Applications Centerin connection with the AKL’06 con-ference.

11.05.2006Chair for Laser Technology LLTat RWTH AachenLecture in association with the RWTH Colloquium on LaserTechnologyProf. Philip Russell, Institut für Optik,Universität Erlangen-Nürnberg»Photonic crystal fibres (PCFs)«

23.05.2006, AachenUnihits for KidsForum organized by the Chair for Laser Technology LLT and theFraunhofer ILT to give advice onscientific careers to students at theGGS Laurensberg.

Above: The exhibition accom-panying the conference at AKL’06.Middle above: Award of theLasertechnik early-stage researchprize to Dr.-Ing., Dipl.-Wirt. Ing.Karsten Schneefuß (2nd fromleft) on May 3, 2006.Middle below: Live laser tech-nology demonstrations at theFraunhofer ILT during AKL’06 onMay 5, 2006.Below: Award of the Lasertechnikinnovation prize to Professor Dr.-Ing. Horst Exner (2nd from left)and Dipl.-Ing. Stefan Wischmann(3rd from left) on May 4, 2006.



31.05.2006, AachenAachen Laser Seminar»Advance by laser surfaceengineering - deposition welding,repairs, cleaning and polishing«Seminar organized by Carl HanserPublishers, Munich in associationwith the Fraunhofer Institute forLaser Technology ILT, Aachen. Additional information:www.aachenerlaserseminare.de.

01.06.2006Chair for Laser Technology LLTat RWTH AachenLecture in association with the RWTH Colloquium on LaserTechnologyProf. Karsten König, Fraunhofer-Institut für Biomedizinische TechnikIBMT, St. Ingbert»Multiphotonen-Tomographie undNanochirurgie mittels Femtosekun-den-Laser«

08.06.2006Chair for Laser Technology LLTat RWTH AachenLecture in association with theRWTH Colloquium on LaserTechnologyProf. Thomas Schmitz-Rode, Institutfür Biomedizinische Technologien,RWTH Aachen»Mikro- und Nanomedizin: Heraus-forderungen und Chancen für dieMedizintechnik«

21.06.2006, AachenUnihits for KidsForum organized by the Chair for Laser Technology LLT and theFraunhofer ILT to give advice onscientific careers to students at theGymnasium Baesweiler.

06.07.2006Chair for Laser Technology LLTat RWTH AachenLecture in association with the RWTH Colloquium on LaserTechnologyProf. Peter Hering, Forschungszentrum »Caesar«, Bonn»Moderner Lasereinsatz in Medizin,Umwelt und Life Science«

20.07.2006Chair for Laser Technology LLTat RWTH AachenLecture in association with theRWTH Colloquium on LaserTechnologyDr. Holger Lubatschowski, LaserZentrum Hannover, Bereich Medizin/Biophotonik»Anwendungspotential ultrakurzerLaserpulse in Medizin und Life science«

22.09.2006, Hamburg24th seminar of the »Aix LaserPeople«the alumni club of the FraunhoferILT and the Chair for Laser Techno-logy LLT, featuring a presentation ofthe company PS Laser GmbH & Co.KG, Thedinghausen, by Dipl.-Ing.Lutz Abram, followed by a visit tothe company’s premises, and ano-ther visit to Rofin-Sinar Laser GmbHin Hamburg, where a lecture washeld by the company’s managingdirector Dipl.-Ing. Thorsten Frauen-preiß on the subject of »Innovationprocesses at Rofin-Sinar«.

27.09.2006, AachenUnihits for KidsForum organized by the Chair for Laser Technology LLT and theFraunhofer ILT to give advice onscientific careers to students at theCouven-Gymnasium.

03.11.2006, Aachen25th seminar of the »Aix LaserPeople«the alumni club of the FraunhoferILT and the Chair for Laser Techno-logy LLT, featuring lectures by Dr.Arnold Gillner, Fraunhofer ILT, on»Laser applications in the field ofmedical engineering at the Fraun-hofer ILT«, and by Dr. Hubert Kunze,Boehringer Ingelheim micro-PartsGmbH, Dortmund, on »Respimat®Soft Inhaler: The development of aninnovative inhaler for the treatmentof respiratory problems«. The lec-tures were followed by a visit to thePhilips research center in Aachen.

20.11. - 21.11.2006, AachenAachen Laser Seminar»Online quality assurance oflaser joining processes – reliableand efficient laser-beam welding«Seminar organized by Carl HanserPublishers, Munich in associationwith the Fraunhofer Institute for Laser Technology ILT, Aachen. Additional information:www.aachenerlaserseminare.de.

22.11.2006, AachenAachen Laser Seminar»Innovative laser cutting andwelding processes for metalmachining applications«Seminar organized by Carl HanserPublishers, Munich in associationwith the Fraunhofer Institute for Laser Technology ILT, Aachen. Additional information:www.aachenerlaserseminare.de.

23.11.2006, AachenAachen Laser Seminar»Laser metrology for the metalworking industry«Seminar organized by Carl HanserPublishers, Munich in associationwith the Fraunhofer Institute for Laser Technology ILT, Aachen.Additional information:www.aachenerlaserseminare.de.

07.12.2006Chair for Laser Technology LLTat RWTH AachenLecture in association with theRWTH Colloquium on LaserTechnologyHans-Joachim Cappius, Laser- undMedizin-Technologie GmbH, Berlin»Optische Technologien in derMedizintechnik«

13.12.2006, AachenUnihits for KidsForum organized by the Chair for Laser Technology LLT and theFraunhofer ILT to give advice onscientific careers to students at theOtto-Hahn-Gymnasium in Mon-heim am Rhein.

14.12.2006Chair for Laser Technology LLTat RWTH AachenLecture in association with the RWTH Colloquium on LaserTechnologyDr. Frieder Loesel, Perfect VisionOptische Geräte GmbH, Heidelberg»Ultrakurzpulslaser in der Medizin -Sanftes Licht für präzise Therapie«

21.12.2006, Aachen26th seminar of the »Aix LaserPeople«the alumni club of the FraunhoferILT and the Chair for Laser Techno-logy LLT, featuring lectures by Dr.Willi Neff, Fraunhofer ILT, on »Newdevelopments from the departmentof plasma technology at the Fraun-hofer ILT«, by Dr. Rainer Lebert,managing director of AIXUVGmbH, Aachen, on the subject of»AIXUV GmbH - short-wavelengthemissions (EUV) in industry andscience«, and by Dr. Joseph Pan-kert, Philips Lighting B.V., Eindho-ven, on »Philips Extreme UV GmbH- lithography plants for the nextgeneration of integrated circuits«.The lectures were followed by visitsto the premises of AIXUV GmbHand Philips Extreme UV GmbH inAachen.



Above: Lecture at the »AachenLaser Seminar«. Middle: Demonstrations at the»Aachen Laser Seminar«. Below: 24th seminar of the »AixLaser People« in Thedinghausen.

21.03. - 23.03.2006Shanghai, ChinaLASER. World of Photonics China International trade show and congressParticipation by the Fraunhofer ILTat the group stand hosted by MesseMünchen,ILT topic: laser beam sources andapplications.

24.04. - 28.04.2006HannoverHannover Messe 2006 International show for industrialtechnologiesThe micro technology departmentof the Fraunhofer ILT exhibited atthe group stand hosted by IVAM,ILT topic: lasers in micro technology,exhibit: spiral drilling optics.

09.05. - 12.05.2006SinsheimMicrosys Congress and exhibition on micro-systems engineering and precisionmanufacturing,Participation by the Fraunhofer ILTmicro technology department, ILT topic: laser-beam micromachining.

13.06. - 16.06.2006Oyonnax, FranceFIP 2006 International Plastics Industry Exhibition FIPParticipation by CLFA at the groupstand hosted by the company SMT,CLFA topics: laser applications for die- and tool-making, and thepotential of selective laser melting(SLM) as a method of direct manu-facturing.

24.09. - 27.09.2006Johannesburg, South Africa INSITE 06 International Science, Innovationand Technology ExhibitionParticipation by the Fraunhofer ILTsystem technology department at the group stand hosted by BMBFand DAAD,ILT topic: applications in the fieldsof welding and generation.

24.10. - 28.10.2006HannoverEuroBLECH International Sheet Metal WorkingTechnology ExhibitionParticipation by the Fraunhofer ILTsystem technology department atthe Fraunhofer-Gesellschaft groupstand,ILT topic: process monitoring inlaser materials processing.

07.11. - 09.11.2006Friedrichshafenparts2cleanTrade Fair for Parts Cleaning andDrying TechnologyParticipation by the Fraunhofer ILTsurface treatment department at the group stand hosted by theFraunhofer Cleaning TechnologyNetwork,ILT topic: laser-beam cleaning.

15.11. - 17.11.2006DüsseldorfComPaMED International Trade Fair for Com-ponents, Parts and Raw Materialsfor Medical ManufacturingParticipation by the Fraunhofer ILTmicro technology and surface treat-ment departments at the IVAMgroup stand,ILT topics: laser-beam transmissionwelding of plastics without theaddition of absorbers, microdrillingof holes for dosing devices and thefixing of implants, and the fabrica-tion of implants by means of selec-tive laser melting.


Trade Fairs

Above: Hannover Messe 2006.Minister Prof. Dr. Andreas Pinkwart(right) und Dipl.-Ing. Welf Wawers(Fraunhofer ILT).Middle: INSITE 06, Johannesburg,South Africe. From left: MosibudiMangena, South African Ministerof Science and Technology, Fraunhofer senior vice-president Dr. Alfred Gossner, Olaf Köndgen,DAAD Bonn, Dr. Stefan Kaierle,Fraunhofer ILT.Below: Fraunhofer ILT stand atComPaMED 2006, Düsseldorf.

»Your partner for innovation«(German/English)This brochure provides a concise over-view of the Fraunhofer ILT. In additionto presenting a summary of EuropeanR&D projects conducted by the ILT, thebrochure also contains a short profileof the institute as well as a list of refe-rence customers.

»Services and Contacts 2006/7« (German/English)This brochure gives an overview of current services offered and contactswithin the Institute. It also introducesfocal points of each division of theFraunhofer ILT.

Annual Report 2006(German/English)The annual report presents a compre-hensive look at the R&D activities ofthe Fraunhofer ILT for the respectivebusiness year. Lists of scientific publi-cations and lectures as well as patents,dissertations, conferences and tradefairs are also included. The English ver-sion can only be found on our websiteat: www.ilt.fraunhofer.de.

Proceedings of the Aachen Collo-quium for Laser Technology AKL’06The technical proceedings of theAachen Colloquium for Laser Techno-logy AKL’06 (May 3 - 5, 2006) containsreports from 34 laser manufacturersand users outlining the latest develop-ments and technology trends in in-dustries such as optics, automobile,metal production, tool and die makingas well as electrical and electronicengineering. Practical case studies highlight various laser processes suchas laser beam welding and cutting,laser surface technology as well aslaser micro engineering.

Proceedings of the TechnologyBusiness day TBT’06The proceedings of the TechnologyBusiness Day, which took place on03.05.2006 in Aachen with a panel of 13 experts in financial services,technology marketing, law, sales andbusiness consulting, are addressed pri-marily toward managers of expandinghigh-tech firms and newly establishedsmall companies. The publication pro-vides a succinct overview of the emerg-ing trends and opportunities offered bylaser technology, mechanical and auto-motive engineering. At the same time,it also sheds light on many financial,legal and marketing questions confront-ing businesses at various stages of theirevolution.

Technical Brochure: »High-Power Diode Lasers« This technical brochure outlines thevarious development activities of theFraunhofer ILT in the area of high-power diode lasers. Included are developments such as the design ofspecial components for laser cooling,diode laser bar packaging, diode laserburn-in characterization and the opticaldesign and development of completediode laser modules.


Publications

ILT

InstitutLasertechnik

Fraunhofer

TAGUNGSBAND

03 . - 05 . MAI 2006

EUROGRESS AACHEN

Technical Brochure: »LASIM® -Laser Simulator for Training« This technical brochure gives an overview of the advantages of usingmultimedia software to train laserusers and students. It introduces theapplication fields, program contentsand the system demands of the LASIM®

software. This was developed at theFraunhofer ILT for the training of laserwelding and cutting. The LASIM® CDROM with corresponding programinstructions is available at the FraunhoferILT.

Technical Brochure: »Laser Tech-nology for Surface Modificationand Forming« This technical brochure provides anoverview of how lasers are employedin the area of surface modification andforming. Included are processes suchas deburring, melting and forming,polishing, roughening, structuring andactivation, re-crystallization, annealingand fine pearlitizing.

Technical Brochure: »Laser Technology for Wear and Corrosion Protection« Wear and corrosion protection can becreated by various laser processes. Thistechnical brochure provides insightsinto processes such as martenistic sur-face hardening, remelting, depositionwelding, alloying and dispersion.

Technical Brochure: »Laser BeamDeposition Welding« This technical brochure provides anintroduction to the processes andsystems used in laser beam depositionwelding. It also elucidates the differen-ces between conventional powderfeed nozzles and those used in laserbeam deposition welding.

Technical Brochure: »Rapid Proto-typing and Rapid Manufacturing of Metal Parts« This brochure describes the selectivelaser melting process developed at theFraunhofer ILT which enables complexmetal parts to be manufactured directlyfrom 3D CAD data. It also providesexamples of applications of the laserbeam generation technique.

Technical Brochure: »Lasers in Microstructuring« This technical brochure describes processes such as laser ablation, precision cutting, drilling and laser-assisted microforming.

Technical Brochure: »Laser Ablation, Cleaning and Marking«This technical brochure outlines the advantages of the different laserprocesses and the wealth of potentialapplications.

Technical Brochure: »Systems and Equipment for Laser MaterialsProcessing«This technical brochure highlights thesystems engineering solutions availableto Fraunhofer ILT customers. Theyencompass the planning, developmentand installation of complete laser facilities and process monitoring andcontrol systems, complemented by fea-sibility studies, training and educationseminars and consulting services.

Technical Brochure: »Quality Assu-rance in Laser Materials Processing«This technical brochure explains thepotential for process monitoring andcontrol in laser materials processing. Italso outlines the services available fromthe Fraunhofer ILT for the developmentof such monitoring systems.


Publications

Lasertechnik für die Oberflächen-modifikation und das Umformen

Technical Brochure: »Lasers in Mounting and ConnectingTechniques«This technical brochure gives an over-view of the use of laser technology inmounting and connecting techniques.Micro joining processes such as laserbeam bonding and laser beam solder-ing are demonstrated.

Technical Brochure: »Lasers in Plastics and Paper Processing« This technical brochure describes theuse of lasers in the processing of plastics,composite materials, paper and glass.

Technical Brochure: »Lasers in Life Science« This technical brochure deals withapplications of laser technology inmedical engineering. It also describesthe use of lasers as tools in microreac-tion processes and biotechnology.

Technical Brochure: »Modeling and Simulation« Written by experts, this brochure pro-vides an overview of the activities andcore competencies of the projectgroup on modeling and simulation. ILTspecialists and researchers at the Chairfor Laser Technology LLT of RWTHAachen University devise models tosimulate resonator design conceptsand beam-guiding and focusingsystems, and a variety of machiningprocesses including cutting, weldingand drilling.

Technical Brochure: »Laser Microscopy«A brochure offering insights intoadvanced techniques of laser scanningmicroscopy developed at the Fraun-hofer ILT.

Information Brochure:»Optical Technology Courses at RWTH Aachen«This brochure summarizes the lasertechnology courses available at RWTHAachen and is designed specifically for students of mechanical and electricalengineering as well as physics. The brochure details the courses and lectureson laser technology available to studentswithin their major field of study that aretaught by the individual RWTH chairsunder the auspices of the Fraunhofer ILT.

Information Brochure: »Networks of Competence« »Networks of Competence« was setup on the initiative of the BMBF andserves as an international marketinginstrument and presentation showcasefor the most highly skilled networks ofcompetence in Germany. Its Internetportal, at: www.kompetenznetze.de,with its efficient search engine andmany useful links, provides an idealinformation source and communica-tion platform for individuals and orga-nizations in Germany and elsewherelooking for information and potentialworking partners.

Information Brochure: »European Laser Institute ELI« This brochure provides information onthe European network of recognizedcenters of R&D in laser technologycoordinated by the Fraunhofer ILT. The members of this network have setthemselves the goal of making existinglaser know-how in Europe accessibleto all interested parties in industry and science. The project is sponsoredby the European Commission. Furtherinformation can also be found at:www.europeanlaserinstitute.org.

Product and Project DataDescriptions of projects from theFraunhofer ILT annual reports and specific product information can bedownloaded from our website at:www.ilt.fraunhofer.de.

148 Fraunhofer ILT Jahresbericht 2005

Publications

Laser in Life Science

Laser in der Kunststoff-und Papiertechnik

»Laser technology for manufac-turing« by Reinhart Poprawe

Principles, prospects and examples for the innovative engineer.

Applied laser technology is too wide-ranging a topic to be covered in asingle volume. For this reason, thebook places special emphasis on lasertechnology as used in manufacturingapplications, particularly present-daymachining processes used in produc-tion technology. The phenomenaoccurring in laser-based materials pro-cessing are quantified by formulae andillustrated with corresponding modelsthat are readily understood by the trained engineer or physicist. Thesebasic principles enable the differenttypes of machining operations to besystematically characterized, permittingthe various applications to be illustra-ted using a common scientific basis. Of more practical significance are theprocesses described for various machin-ing operations, which explain in simpleterms the basic principles and keyquantitative interrelationships betweenthe process parameters. The numerousexamples are intended to spark thereader’s creativity and help to inspirenew applications.

ContentsIntroduction, behavior of electromag-netic radiation at interfaces, absorptionof laser radiation, energy transfer andthermal conduction, thermomechanics,phase transformation, melting poolflows, laser-induced ablation, plasmaphysics, laser radiation sources, surfacetechnologies, forming, rapid prototyp-ing, rapid tooling, joining, ablation anddrilling, cutting, systems engineering,laser measuring technologies.Appendices: A: optics, B: continuummechanics, C: laser-induced ablation,D: plasma physics, E: explanation of symbols and constants, F: color images, index

2005. XVII, 526 pages, 353 illustrations(VDI publication), ISBN 3-540-21406-2

The book can be ordered from:Springer KundenserviceHaberstraße 769126 HeidelbergTelefon: +49 (0)6221/345-0Fax: +49 (0)6221/[email protected]


Technical Book »Laser Technology for Manufacturing«


Video »Laser - the ExtraordinaryLight for Material Processing« (German/English)

This training video was made at theBergische Universität - Gesamthoch-schule Wuppertal in cooperation withthe VDI-Technologiezentrum in Düssel-dorf, the Fraunhofer ILT and other lasercenters and companies and a new pro-duction was made in 2000. It deliversan overview of all important lasermachining processes and was speciallymade for use at colleges, universities,technical colleges, vocational schoolsand internal company training. Thisespecially applies to manufacturingengineering courses of study. The VHSvideo is 42 minutes long and is avail-able in both English and German fromthe Bergische Universität - Gesamt-hochschule Wuppertal, Fachbereich D,Abteilung Maschinenbau.

Contact:Prof. Helmut RichterPhone: +49 (0)202/[email protected]

CD-Rom »Laser Technology« (German only)

This CD-ROM is a collection of graphics,pictures and videos from the lecturesLaser Technology I and II by Prof. Dr. rer. nat. Reinhart Poprawe M.A.and a new revised version was producedin 2003.

It was produced by the Department for Laser Technology LLT in the machinefaculty at the Technical UniversityAachen RWTH in close cooperationwith the Fraunhofer Institute for LaserTechnology ILT.

It contains the basics of laser technologyas well as physical and technical pro-cesses for modern manufacturing pro-cesses. Furthermore, the current stateof economic use of laser and industrialapplications is demonstrated in nume-rous examples.

The program runs using Acrobat Reader5.0 on computers with Microsoft Windows 95 OSR 2.0, Windows 98 SE,Windows Millenium Edition, WindowsNT 4.0 with Service Pack, Windows2000, Windows XP and MacOSX (64 MB Ram (random access memory)as well as 30 MB free fixed-disk storage).

The printing and use of unaltered graphics and pictures is only allowedfor educational purposes.

Further information and order formsfor the CD-ROM »Laser Technology«are available through the laser technology association AKL e.V., Steinbachstraße 15, 52074 Aachen.

Contact:Diana HeinrichsPhone: +49 (0)241/8906-122Fax: +49 (0)241/[email protected]

Video Films and Multimedia Software

Multimedia Software LASIM®

(German/Englisch)

LASIM® is a multimedia training program for laser cutting and welding.The combination of text, pictures,sound and animation within the multi-media software has opened new horizons in laser training. In the theo-retical part of the curriculum, compli-cated processes and models are vividlypresented. This contributes to a betterunderstanding of the material. In thepractical part of the training, nume-rous experiments can be made throughsimulations. The user can personallyset the process parameters withoutcausing problems in the real lasersystem.

By installing several computer worksta-tions, personnel costs can be reduced.Furthermore, the multimedia programis suited for private study. The laseruser is able to work on experiments onthe virtual system at any time.

Multimedia technology ideally supple-ments practical training on real lasersystems. In the initial phase, the exer-cises are conducted at a beginner level.In the following phases, the user isable to use the knowledge acquired tosolve concrete problems on real lasersystems.

The advantages of using multimediasoftware for training of specialists andstudents are obvious:• Visualization of complex correlations

and process development• Simulation of a real laser workstation• Ability to carry out experiments on

virtual systems with evaluation of results

• Unlimited availability and no risk from operator error

• Low support costs and suitability for private study

• Interactive theoretical and practical exercises to strengthen knowledge

The software LASIM® is obtainablefrom the Fraunhofer Institute for LaserTechnology in both German andEnglish. Current information and orderforms are available through the inter-net site www.ilt.fraunhofer.de.

Contact:Dr. Dirk PertringPhone: 49 (0)241/8906-210Fax: 49 (0)241/[email protected]


Video Films and Multimedia Software


Information-Service

Sender

_________________________________________Last Name, First Name

_________________________________________Company

_________________________________________Division

_________________________________________Address

_________________________________________City/ZIP

_________________________________________Phone

_________________________________________Fax

_________________________________________E-mail

Please fax to:Fraunhofer ILTStefanie FlockFax: +49 (0)241/8906-121

If you would like more informationabout the research and developmentat the Fraunhofer Institute for LaserTechnology please go to our website at www.ilt.fraunhofer.de. Informationcan also be ordered using this form.

Brochure: »Your partner for innovation«GermanEnglish

Brochure: »Services and Contacts 2006/7« (German/English)

Annual Report 2006 (English version only available online at www.ilt.fraunhofer.de)




Proceedings of the Aachen Colloquium for Laser Technology AKL’04 (only German)

Proceedings of the Laser-Business-Day of the AKL’04 (only German)

Proceedings of the Aachen Colloquium for Laser Technology AKL’06 (only German)

Proceedings of the TechnologyBusiness Day TBT’06 (only German)

Technical Brochure: »High-Power Diode Lasers« GermanEnglish

Technical Brochure: »LASIM® -Laser Simulator for Training«GermanEnglish

Technical Brochure: »Lasertechnik für die Oberflächenmodifikation und das Umformen« (Laser Tech-nology for Surface Modification and Forming) (only German)

Technical Brochure: »Lasertechnik für den Verschleiß- und Korrosions-schutz« (Laser Technology for Wear and Corrosion Protection) (only German)

Technical Brochure:»Laserstrahlauftragschweißen«(Laser Beam Deposition Welding)(only German)

Technical Brochure:»Rapid Prototyping and Rapid Manufacturing GermanEnglish

Technical Brochure:»Lasers in Microstructuring«GermanEnglish

Technical Brochure:»Abtragen, Reinigen und Markieren mit Laserstrahlung« (Laser Ablation, Cleaning and Marking) (only German)

Technical Brochure: »Systems andPlant for Laser Materials Processing« (only German)

Technical Brochure: »Quality Assurance in Laser Materials Processing« GermanEnglish

Technical Brochure: »Lasers in Mounting and Connecting Techniques«GermanEnglish

Technical Brochure: »Lasers in Polymer and Paper Technology« GermanEnglish

Technical Brochure: »Lasers in Life Science«GermanEnglish

Technical Brochure: »Modellie-rung und Simulation« (Modeling and Simulation) (only German)

Technical Brochure: »Laser-mikroskopie« (Laser Microscopy) (only German)

Information Brochure: »Optische Technologien an der RWTH Aachen« (Optical Technology Courses at RWTH Aachen) (only German)

Information Brochure: »Networks of Competence«(German/English)

Information Brochure: »European Laser Institute ELI« (only English)

CD-Rom »Lasertechnik« (Laser Technology) (only German)

Technical Book »Lasertechnik fürdie Fertigung« (Laser Technologyfor Manufacturing) (only German)

Multimedia Software LASIM®

German English

Editorial staffDipl.-Phys. Axel Bauer (responsible)Stefanie Flock

Design and ProductionDipl.-Des. Andrea Croll

PrintDruckspektrumHirche-Kurth GbR, Aachen

PaperThis Annual Report was printed on environment-friendly, unchlorinatedand acid-free bleached paper.

Contact Dipl.-Phys. Axel BauerTelephone: +49 (0)241/8906-194Fax: +49 (0)241/[email protected]

Subject to alterations in specificationsand other technical information.

All rights reserved. Reprint only withwritten permission of the editorial office.

© Fraunhofer-Institut für Lasertechnik ILT, Aachen 2007

Fraunhofer-Institutfür Lasertechnik ILT

Steinbachstraße 1552074 AachenTelephone: +49 (0)241/8906-0Fax: +49 (0)241/8906-121

[email protected]


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