Laser Drilling of Cylindrical

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Laser Drilling of Cylindrical and Shaped Holes
NCMS/CTMA Symposium Track 1b Terry L.
VanderWert PRIMA 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 Technology

• 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 small holes translates into
  substantially lower cost.
• No tooling means lower cost, faster turnaround
  the tool is a 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, and machined components, uncoated and with
  TBC
• Rates 0.25 to 5 holes per second

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Laser Drilling of Shaped Cooling Holes

• Film cooling holes increase efficiency of cooling
  air by 30, reducing the amount of air required
  for cooling.
• Used sparingly today because of their cost when
  produced using EDM.

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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

The bottom line? More consistent holes
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Repair Applications for Laser Drilling

• Re-drilling of cooling holes.
• Some cooling holes become blocked during repairs
  by welding or brazing
• Holes must be re-drilled to restore component
  airflow.

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Repair Applications for Laser Drilling

• Removal of TBC overspray
• Coatings must be removed before any repairs can
  take place.
• Re-coating partially fills cooling holes and this
  must be removed to restore component airflow.

Repaired components must be re-coated. The new
coating covers existing cooling holes
Coating must be stripped from components before
repair.
Coating overspray removed by Laser
Issue Amount of new coating in the hole varies
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Potential benefits of laser drilling for repair
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
• Identify actual hole locations
• In process gauging - improve process efficiency
  and quality by automating part inspection

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Laser source technology for combined machining
and drilling

• Objective - Develop laser source capable of both
  pulsed drilling of cylindrical holes and ablative
  machining of shaped holes.
• Challenges Produce laser source having both ms
  (deep hole drilling) and µs (machining) pulse
  widths, with high beam quality.

• Potential return Improve productivity and
  reduce cost for laser drilling by taking
  advantage of the speed of laser machining and
  producing complete shaped holes in a single setup.

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Laser Drilling Capability is Source Dependent
Mechanism

• Throughput holes/second minutes/hole
• Feature size f (wavelength, lens focal length,
  beam diameter, beam quality)
• Debris 10s µm negligible
• HAZ/recast tens to hundreds µm less than 10 µm
• Depth control inversely related to removal rate

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Automation of Setup and Drilling

• Objective Develop vision and probing tools to
  gauge the shape and hole location of repaired
  components.
• Challenges - Parts are deformed shape will not
  match that of the new component. However, the
  repair holes must be 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
  laser machines.

• Potential return
• Higher quality components.
• Greater machine utilization by avoiding
  inefficiencies of removing/resetting the part
  into the drilling 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
  improve productivity, reduce dependence on
  skilled operators, and improve consistency in
  repair operations.
• PRIMA North Americas 20 years history of
  innovation in lasers for turbine engine
  manufacturing and repair will reduce risk and
  cost of these developments.