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7/29/2019 Food and chicken

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Laser Drilling of Cylindrical

and Shaped Holes

NCMS/CTMA Symposium: Track 1b

Terry L. VanderWertPRIMA North America, Inc.


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Outline

Laser drilling technology overview

Capability Applications Recent developments benefits of integration

Repair applications Potential benefits

Potential projects

Summary


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Customers

Serving Turbine Engine Manufacturers


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Laser Drilling - An Enabling Te chnology

Incremental improvements have led to substantial increases in

the number of cooling holes in new engine designs.

Laser drilling is fast relative to competing methods for smallholes translates into substantially lower cost.

No tooling means lower cost, faster turnaround the tool isa focused beam of light

Flexible single part lot sizes Easily interfaced with CAD/CAM

Drills/machines a wide range of materials At shallow angles Complex shapes


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Laser Drilling of Cylindrical Cooling Holes

Typical applications Cooling holes in blades, vanes,combustors, and afterburners

0.3 to 1 mm diameter holes at 15-90 in cast, sheet, andmachined components, uncoated and with TBC

Rates 0.25to 5holes per second

Airfoil

Air flow

Film cooling holes


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Laser Drilling of Shaped Cooling Holes

0.8 - 1.2mm

0.8 - 1.2mm

10-30 degrees

Wine Glass Shape

(Fan in, Fan out)

Race Track Shape

(Fan in, straight out)

Top View

1. Pierce undersized through hole2. Trepan fan shape- through hole

3. Finish through hole to size(trepan to exit hole diameter)

Top View

1. Pierce undersized through hole2. Trepan fan shape- through hole

3. Finish through hole to size(trepan to exit hole diameter)

Film cooling holes increase efficiency ofcooling air by 30%, reducing the amountof air required for cooling.

Used sparingly today because of their

cost when produced using EDM.

0.4-1.2 mm

1.5-3.0 mm12-20degrees


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Recent Developments by PRIMA North America

for New Part Manufacturing and Repair

Process control for improved airflow consistency Optimum laser process parameters for cylindrical shaped

holes Drill at focus

Breakthrough detection

Optical focus control (for TBC)

Simple shaped hole drilling

Distribution of Exit Hole Diameter

0.50 0.60 0.70 0.80 0.90

Hole Diameter, mm

Without Breakthrough Detection

Breakthrough Detection

The bottom line? More consistent holes


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Repair Applica t ions for Laser Drilling

Re-drilling of cooling holes.

Some cooling holes become blocked during repairs bywelding or brazing

Holes must be re-drilled to restore component airflow.

Blades and vanesrepaired by

welding orbrazing.

Cooling holesbecome blockedand component

suffers somedistortion

Cooling holes re-drilled by laser


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Repair Applica t ions for Laser Drilling

Removal of TBC overspray

Coatings must be removed before any repairs can takeplace.

Re-coating partially fills cooling holes and this mustbe removed to restore component airflow.

Coating must bestripped from

componentsbefore repair.

Repaired componentsmust be re-coated.The new coating

covers existingcooling holes

Coating overspray

removed by Laser

Issue: Amount of

new coating in thehole varies


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Potential benefits of laserdrilling for repa ir depots

Reduced costs

Reduced turnaround time - keep aircraft flying

Provides a method for producing engines

having increased engine performance Thermal barrier coatings Film cooling shaped and cylindrical


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Potential Projects

Laser source technology for combined machining and

drilling in uncoated as well as thermal barrier coated (TBC)

components

Automation of set-up and drilling Probe repaired components to compensate for

deviations in shape and position

Identifyactual hole locations

In process gauging - improve process efficiency andquality by automating part inspection


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Laser source technology for

combined machining and drilling

Objective- Develop laser source capable of both pulseddrilling of cylindrical holes and ablative machining ofshaped holes.

Challenges Produce laser source having both ms (deephole drilling) and s (machining) pulse widths, with highbeam quality.

Potential return Improve productivity andreduce cost for laser drilling by takingadvantage of the speed of laser machining and

producing complete shaped holes in a singlesetup.


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Laser Drilling Capability is Source Dependent

Throughput holes/second minutes/hole

Feature size f (wavelength, lens focal length, beam diameter, beam quality)

Debris 10s m negligible

HAZ/recast tens to hundreds m less than 10 m

Depth control inversely related to removal rate

4 FBeam = M

2

D4 F

Beam = M2

D

CW fs

Melt expulsionVaporization Ablation

ColdAblation

PulsedNd:YAG(ms/s)

Q-switchedNd:YAG

(ns)

Ti:Sapphire(fs)

Nd:YVO4(ps)

Cu vapor(ns)

Excimer(ns)

Coarse to fine

CW fs

Melt expulsionVaporization Ablation

ColdAblation

PulsedNd:YAG(ms/s)

Q-switchedNd:YAG

(ns)

Ti:Sapphire(fs)

Nd:YVO4(ps)

Cu vapor(ns)

Excimer(ns)

Coarse to fineMechanism

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E-12 1.E-09 1.E-06 1.E-03 1.E+00

Pulse duration, sec

Removalrate,mm^3/sec


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Automation of Setup and Drilling

Objective Develop vision and probing tools to gauge theshape and hole location of repaired components.

Challenges - Parts aredeformed; shape will not match that

of the new component. However, the repair holes mustbe coincident with the original holes.

Potential return Improved productivity by automating

time-consuming setup steps.


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In Process Gauging

Objective Actively monitor component airflow to

determine which holes should be re-drilled.

Challenges Integration of gauging tools with lasermachines.

Potential return Higher quality components.

Greater machine utilization byavoiding inefficiencies ofremoving/resetting the part into thedrilling system.


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Summary

Improvements in laser drilling technology for modern,

new component manufacturing can benefit repair whether at the repair depot or commercial partner.

Additional technology development is needed to improveproductivity, reduce dependence on skilled operators, andimprove consistency in repair operations.

PRIMA North Americas 20+ years history of innovationin lasers for turbine engine manufacturing and repair willreduce risk and cost of these developments.

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