2-2008

Technical Magazine for the World's Paper, Film and Foil Converting Industries

E 14009Volume 14 · Juni 2008

Flexo&GravureInt'lFlexo&GravureInt'l

A G&K TechMedia Publication Made in Germany

80 FLEXO & GRAVURE INT'L 2-2008

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COMPANY REPORT○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

VOLKER SCHLEVOIGT

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No matter how many innova-tions packagers demand from

their printers and converters, andno matter how much tighter theymake their production specifica-tions, the flash of stroboscopic in-spection lights remain a consistentway to ensure a quality package fortheir quality products.

Over the past few years we haveseen a growing demand for pack-ages with security codes to ensureconsumers get authentic food anddrug products and that automobileand aerospace companies get genu-ine spare parts. We have also seenmore new materials that providebetter packages for foods and drugs,and we talk to product manufactur-ers who simply want better qualitypackaging to give them an edge inthe highly competitive retail mar-kets.

Through all of the product andsecurity upgrades, stroboscopic in-spection lights have provided flexo-graphic and gravure printers with aconsistent technology that helpsthem satisfy their customers andtheir customers’ customers. In timesof high-tech developments, strobe-light technology is constantly im-proving, but the principle remainsthe same. Strobe-lights give ma-chine operators real-time inspec-tion capability at full productionspeeds by freezing images of theentire web to make defects stand

Stroboscopic inspection lights helppackage printers meet customer needs

Marketing Director for Europe, the Midd-le East and Africa, Unilux Inc, SaddleBrook, NJ/USA. www.unilux.com

out. Operators can use their knowl-edge of the process and product toquickly make a number of decisionsthat greatly reduce waste, improveproduction and guarantee a qualityproduct is produced.

Meeting quality demand

The recent installation of nine Uni-lux strobe lights at Pilenpak Am-balaj, Manisa/TR, helped the com-pany restore customer confidencein its packaging products for a va-riety of foods. Pilenpak has main-tained a 20% market share since itsfounding in 1988, but questionsabout tiny unconformities, such assmall splashes of ink or some littlespots had been a problem for 15years. Company managers knewthere was always a danger of losingaccounts, especially in the marketswhere visual tolerances are ex-tremely narrow.

»We had tried to explain thatwith high-speed printing presses,operators cannot see the images asthey pass by at speeds of 300 m/min(985 fpm)– or 5 m/sec«, said GÜNERI

TASÇIOGLU, the company’s produc-tion manager.

But that was not the kind ofresponse that built customer confi-dence. Thus, GÜNERI TASÇIOGLU wasreceptive to a phone call from DENIZ

DERAL, Sales Manager for BordenEngineering, Unilux’s representa-tive in Turkey. Pilenpak knew thatstrobe lights provided a still imagefrom their use of video inspectionsystems. But these systems onlyallowed viewing of a small area ofthe web. When they saw that theUnilux lights gave them a completefrozen image of the entire web, theywere convinced this was right fortheir needs. Once DENIZ DERAL hadthe specifications for each of theirmachines it was easy to match thecorrect light for each application.

Mr TASÇIOGLU, in turn, was ableto open customers’ eyes just asquickly. »When I showed one of ourcustomers an image we had takenwith a Unilux light on a slittingmachine that was moving at 600 m/

min (1970 fpm)«, he said, »he wassurprised and convinced of our fo-cus on quality and the continuedimprovement of our product.«

Six months after the demonstra-tion, Pilenpak had installed UniluxLOL-40 (Lith-O-Light) lights on theplant’s four Japanese rotogravurepresses – two eight-colour presses, anine-colour press and a 12-colourpress – with 600 mm (25") widthsand on their four slitters and a LOL-20 on a doctoring machine. TheLOL-40 are able to illuminate anarea of 1250 x 300 mm (49.2" x12"), and the LOL-20 can illuminatean area of 650 x 300 mm (25" x 12")from a distance of 300–400 mm(12"–16"). A Unilux HD-851 hasbeen ordered for installation onanother slitter. The brighter light isneeded to illuminate an area of1250 x 1250 mm (49.2" x 49.2") ata distance of 1.5 m (5 ft) and ismounted onto a 2-access slitter toilluminate both coiling rollers.

Pilenpak prints on BOPP, PETand paper to produce flexible pack-aging materials and roll-fed labelsfor food products, such as pasta,candies and chips. When retailersrely on impulse buying, the colourand quality of the packaging is anindication of the quality inside.Pilenpak serves food packagers onfour continents, and quality is im-portant. The company is TS-ISO-EN9000 and BRC-IOP certified and haspassed numerous audits for foodsafety.

GÜNERI TASÇIOGLU says the lightshave helped press operators spotdefects such as streaks, spots, badregistration and other defects thatcan cause a customer to reject ashipment of packages or labels.Pilenpak also reports reducing itswaste to 0.5% on its film output of12,000 tons per year by reducingthe amount of defective materialgoing through our laminating andslitting processes. As operators seeunconformities in the print runs,they can put flags on the bad sec-tions and cut them out before goingto the value-added laminationprocess. Before adding the inspec-tion lights, the company did notrealize the problems until after

A Unilux LOL-40 strobo-scopic inspection light atPilenpak Ambalaj, Manisa/,TR, freezes the images offood packaging at fullproduction speed, enablingpress operators to seedefects and take appro-priate action to correct theproblem.

© by G&K TechMedia GmbH · D-79261 Gutach · www.flexo-gravure-international.com

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COMPANY REPORT

lamination or even after slitting.Worst case the products couldhave been returned from custom-ers.

Pilenpak is looking at the pur-chase of a similar number of pres-ses, slitters, laminators, doctoringmachines and inspection systemsfor a new plant that will mirrorthe existing plant. Here they alsowill install the Unilux strobo-scopes. The new plant is sched-uled to open in 2008. The compa-ny says future plants will be simi-larly equipped as well as being si-milarly sized. This will make itmuch more efficient for develop-ing production systems andmaintenance routines, trainingoperators and technicians andmaintaining inventories of rawmaterials and spare parts.

Cold-connected

In addition to known applicationsfor stroboscopic lights in theprinting industry we’ll always ex-plore and develop new applica-tions. Thus the cold sealing adhe-sives have gained more impor-tance in the past few years. Theymeet a variety of needs for facto-ry-sealed packaging, especiallyfor sweets, toiletries and cleaningproducts and in some cases for re-sealable packages. These are usedfor products that need to retainfreshness after being openedwhile providing new styles of pa-ckaging in addition to the wellknown container packaging.

The adhesive works when twocoated sections of a substratetouch each other. The contactstarts a chemical reaction thatbonds them. The adhesive is clearand is applied to the packagingmaterial like an ink. For the suc-cess of the connection it is impor-tant that on the one hand there isenough glue used and on theother that the position on thebackside of the packaging isaligned with the front print.

With transparent film, thestroboscopes are installed fromthe backside of the material. Be-cause of the difference from re-flecting film to the matt coatingthe coating can be seen clearly. Inthis mode also the positioning ofthe coating in relation to the print

on the packaging can be seenperfectly. With non-transparentmaterial the strobes will be usedfrom the front side, where thecoating can be seen perfectly inrelation to the used material. Insome cases marks are printed onthe backside of the material dur-ing the printing of the front side.These are then used for position-ing the coating on the backside. Inboth cases the angle the strobesare mounted in relation to thesurface is very important to seethe relation between reflectivefilm and matt coating.

All Unilux stroboscopes canbasically be used for the inspec-tion of cold seal adhesives. Indaily use the LOL-models haveshown their advantages, as theyare designed for widths of 250–1400 mm (10"–56"). In some casesthe model HD-851 has been cho-sen, as it illuminates not only awidth of 1300 mm (52"), but alsoa height of the same dimension.

Hidden security

The need for secure printing forlabels, documents, money, com-pact discs and DVDs and packag-ing has increased in today’s tech-nology-driven world. Softwarehas made it easier than ever fordishonest people to copy artworkand create counterfeit packagingfor counterfeit items, but strobo-scopic inspection with UV illumi-nation filters has made it possibleto provide codes and images toauthenticate real items.

Lottery ticket and game cardprinters have used hidden marksand various clear coats and var-nishes with UV inhibitors in themfor a long time to conceal andprotect the winning informationfor contests and games. In addi-tion to hiding information, coat-ings must be able to withstandmoisture for game cards distrib-uted in bars and restaurants. Prin-ters have their own stake in pro-tecting the integrity of each print-ed ticket or card because they areresponsible to pay the prize as theprice for making a mistake thatvoids a game or contest.

The stakes are higher for com-panies printing government doc-uments, such as currency or pass-

ports. To help with internationalsecurity, some governments havetheir country’s name printed onsheets from which passport cov-ers are cut. The printing is done ina clear coat, using English andnative characters. Because theprinting can only be seen under ablack light, one equipped with aUV lens is used to verify that theprint is properly done.

Similarly, companies and gov-ernments that print money, stockcertificates and other financialdocuments are using variousmarkings and materials that canbe seen only under black-lightinspection which allows the op-erator to inspect under full pro-duction speeds.

Inspection chemistry

Clear coatings and invisible inkspresent a different inspectionproblem than typical printing.They remain invisible under stan-dard strobe equipment becausethe standard quartz lens found onmost industrial-quality lights ac-tually blocks the UV light emit-ted by the strobe. Equipping astrobe-light with a specially de-signed UV lamp and UV lensesexcites the phosphors in the inksand coatings as they pass underthe light. This light is measured innanometers (nm). There are dif-ferent UV lenses for the differentwavelengths, designed for thevarying specification of the UVsensitive inks. In most cases ma-terial is used that is sensitive to UVlight with a wavelength of 360nm.

Depending on the spectrum oflight needed to excite the phos-phorescent chemicals, various

Pilenpak uses a Unilux LOL-40stroboscopic inspection light totake a closer look at the fullweb when an automated inspec-tion system indicates a possibledefect.

FLEXO & GRAVURE INT'L 2-2008 81

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lenses can be used to get the ma-ximum visual effect during in-spection. The 250 nm system wasdeveloped especially for one prin-ter to see some very specific de-tails. The specially equipped lighteliminated the need for qualitycontrol inspectors to pull randomsamples from a press run to checkin a chemistry lab. As a result, in-spectors could view the entirepress run at full productionspeeds; greatly improving thecompany’s operating efficiency.

Label printers also use clearcoatings with waterproofing qua-lities to protect product informa-tion on labels used in the pharma-ceutical and food industries. La-bels may be used to present le-gally required information oncontent within a drug or food and,in the case of pharmaceutical pro-ducts, information about usage,dosage levels, potential side ef-fects, health warnings and otherrelated directives. In the printingprocess, areas may need to be leftblank for the insertion of variableinformation, such as lot numbersand expiration dates, and printersmust verify that those spaces arefree of any coatings or markings.When the variable information isadded, it can be inspected with astandard strobe light, and a sub-sequent protective coating can beinspected with another UV sys-tem.

For car parts, companies suchas Land Rover use UV inks on

© by G&K TechMedia GmbH · D-79261 Gutach · www.flexo-gravure-international.com

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82 FLEXO & GRAVURE INT'L 2-2008

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A strobe-light equippedwith a UV illumination kitshows details on a label(right) that identifies a partas authentic. The informa-tion is not visible withoutviewing under a black light.

their part tags to prevent counter-feiting. Not seen under standardstrobe lights, the security print ishighly visible under a special spec-trum of UV light.

Coatings on product labelsmaintain the integrity of appear-ance during shipping, storage andusage. Label printers for beers arekey examples. While not as con-cerned with counterfeiting, theyrely on clear coatings on the front ofthe label to protect its look and in-tegrity even when severe condensa-tion and moisture conditions occurand reoccur. Printers also need to besure that the proper amount andthickness of glue is applied to thebackside of the label to keep itattached to the container. A UV in-spection kit on a strobe light canverify this when phosphorescentshave been added to the glue.

Installing a system

Setting up a UV inspection station issimilar to setting up a standard stro-

boscopic inspection station exceptthat care must be taken about ambi-ent light. The UV illumination kitsfrom Unilux are designed to fit per-fectly on the lights in the Lith-O-Light series so they can cover a webof any width as with a standard in-spection system. For special appli-cations there are UV lenses for widearea lights as well as handheldstrobes. Existing strobe-lights canbe upgraded with UV kits for a smallamount.

Unilux recommends having aUV system at a point along the webwhere all security printing is com-pleted. If variable information is tobe added at a later station, followedby a protective coating application,a second system should be added atthat point. Additional stations canbe installed on slitters and rewind-ers if those locations best suit a labelprinter’s inspection needs. Inspec-tions at these points can verify thatregistration marks and specialcodes are still intact after post-printing operations. They can also

ensure a good cutting edge on theslitters, or determine the sharpnessof the slitting knife and if it has to bereplaced.

As printing technologies con-tinue to evolve, stroboscopic in-spection will continue to keep pace,providing printers and converterswith the capability to inspect prod-ucts to ensure they look good andperform as required – in a flash.➜ www.pilenpak.com➜ www.unilux.com

© by G&K TechMedia GmbH · D-79261 Gutach · www.flexo-gravure-international.com