Laser maintenance tool

• US 8,927,897 B2
• Filed: 11/17/2010
• Issued: 01/06/2015
• Est. Priority Date: 11/17/2010
• Status: Expired due to Fees

• Current Assignee: Rolls-Royce North American Technologies, Inc. (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce Corporation (Rolls-Royce Holdings Plc)
• Inventors: Xu, Raymond Ruiwen, Fuesting, Timothy Paul, Brindley, William J.
• Primary Examiner(s): Evans, Geoffrey S
• Application Number:
  US12/948,318
• Publication Number:
  US 20120121382A1
• Time in Patent Office: 1,511 Days
• Field of Search: 219/121.68, 219/121.69, 219/121.73, 219/121.83, 219/121.61, 219/121.62, 356/241.4
• US Class Current: 219/121.61
• CPC Class Codes: B23K 26/0624 using ultrashort pulses, i.e. pulses of 1ns or less
• CPC Class Codes: B23K 26/361 for deburring or mechanical trimming B23K26/351 takes precedence
• CPC Class Codes: F01D 25/002 Cleaning of turbomachines
• CPC Class Codes: F05D 2230/72 Maintenance
• CPC Class Codes: F05D 2230/80 Repairing, retrofitting or upgrading methods
• CPC Class Codes: F05D 2260/80 Diagnostics
• CPC Class Codes: G01N 21/954 Inspecting the inner surface of hollow bodies, e.g. bores
• CPC Class Codes: Y10T 29/49229 Prime mover or fluid pump making
• CPC Class Codes: Y10T 29/53 Means to assemble or disassemble

Abstract

In one form a maintenance device includes a flexible member with an inspection end sized to be inserted through an inspection port of a workpiece such as a gas turbine engine or a blade of a gas turbine engine. The maintenance device includes a directed energy member that in one form is configured to produce a double pulse laser with an interval time between a first one of the pulses and a second one of the pulses greater than the time of either the first one of the pulses or the second one of the pulses. The first one of the pulses is sufficiently powerful to produce a quantity of debris upon irradiation of the workpiece. The debris produced from the first one of the pulses can be evaporated by the second one of the pulses to eliminate and/or reduce a recast layer on the workpiece.

Claims

1. An apparatus for emitting electromagnetic energy comprising

an inspection device having a flexible extension that includes an

inspection end sized to be inserted through an inspection opening of an assembly to be repaired;

and

a coherent electromagnetic energy device including a pulse laser operable to emit laser pulses at a discharge, the coherent electromagnetic energy device coupled with the flexible extension of the inspection device and operable to be inserted through the inspection opening of the assembly,

wherein the pulse laser is a double pulse laser configured to emit successive pairings of limited duration laser pulses including a primary and a secondary laser pulse that are each about 3 ns in duration with an average intensity of about 4 Mega Watts per square centimeter producing a maximum power of about 750 kw, and wherein the interpulse time between pairs is between about 30 ns and about 150 ns.

2. The apparatus of claim 1, wherein the inspection device includes a borescope coupled to the flexible extension, the borescope operable to provide an inspection image.

3. The apparatus of claim 1, which further includes an assembly space having positioned within it a gas turbine engine that includes a damaged component, the inspection opening formed within a portion of the gas turbine engine.

4. The apparatus of claim 1, wherein the time between a first pair of limited duration laser pulses and a second pair of limited duration laser pulses is greater than a time between the pulses of either the first pair or second pair.

5. An apparatus comprising

a gas turbine engine construction device having a flexible borescope capable of capturing an image of a component to be operated upon and a laser positioned proximate an end of the flexible borescope to emit successive pairings of laser energy pulses, a first pulse of a pairing operable to produce an ejecta from the component and a second pulse of the pairing operable to disperse the ejecta to improve material processing properties

wherein the first pulse and the second pulse of the successive pairings are each about 3 ns in duration with an average intensity of about 4 Mega Watts per square centimeter producing a maximum power of about 750 kw, and wherein an interpulse time between the successive pairings is between about 30 ns and about 150 ns.

6. The apparatus of claim 5, which further includes a gas turbine engine that has an opening sized to receive the flexible borescope;

wherein the gas turbine engine includes the component to be operated upon; and

further wherein the component is metallic.

7. The apparatus of claim 5, wherein the flexible borescope includes a cross sectional dimension less than about 1 cm along a length of the flexible borescope.

8. The apparatus of claim 5, wherein the laser is a fiber-hosted laser and is capable of providing an average output power of above 1 kW and a peak power of more than 50 kW.

9. The apparatus of claim 5, wherein the second pulse of the pairing vaporizes the recast layer.

10. The apparatus of claim 5, wherein the second pulse of the pairing discourages formation of a recast layer of the component.

11. A method comprising

inserting a flexible portion of a borescope inspection device through an inspection port of a gas turbine engine, the flexible portion having an end coupled with a coherent electromagnetic energy device including a double pulse laser;

emitting a pair of limited duration laser pulses from the coherent electromagnetic energy device to affect a change in physical state of a portion of the gas turbine engine;

producing a quantity of debris from the portion of the gas turbine engine as a result of a first pulse of the double pulse laser irradiating the gas turbine engine; and

heating the quantity of debris with a second pulse of the double pulse laser,

wherein the first pulse and the second pulse of the double pulse laser pulses are each about 3 ns in duration with an average intensity of about 4 Mega Watts per square centimeter producing a maximum power of about 750 kw, and wherein an interpulse time between the successive pairings is between about 30 ns and about 150 ns.

12. The method of claim 11, which further includes flushing the repair location of the gas turbine engine with a working fluid.

13. The method of claim 11, wherein the heating includes superheating the quantity of debris.

14. The method of claim 11, wherein the heating further includes discouraging a recast layer in the gas turbine engine.

15. The method of claim 11, wherein the irradiating includes emitting a laser pulse for about 3 ns.

16. The method of claim 11, wherein the location is a repair location and which further includes imaging the repair location with the borescope inspection device.

17. The method of claim 16, wherein the producing includes removing a damaged portion of a gas turbine engine airfoil.

18. The method of claim 11, which further includes dwelling for a time between the first pulse and the second pulse longer than a duration of the first pulse or the second pulse.

19. The method of claim 18, which further includes emitting another pair of limited duration laser pulses after the pair of limited duration laser pulses, the time between the another pair and the pair being longer than the dwelling.

20. The method of claim 19, wherein the emitting another pair of limited duration laser pulses after the pair of limited duration laser pulses is between 100 μ

s and 100 ms.

21. The method of claim 11, which further includes performing one of a removing material from the portion of the gas turbine engine, building up a material on the portion of the gas turbine engine, joining a component to the portion of the gas turbine engine, and treating the portion of the gas turbine engine.

22. The method of claim 21, wherein the removing includes one of cutting and hole drilling.

23. The method of claim 21, wherein the building includes adding metal.

24. The method of claim 21, wherein the joining includes one of brazing, welding, and bonding.

25. The method of claim 21, wherein the treating includes one of heat treating, peening, re-surfacing, and surface cleaning.

26. An inspection and repair apparatus comprising

an elongate member capable of being flexibly routed within a workpiece and having an imager located near an insertion end of the member capable of capturing electromagnetic energy from within a workpiece;

a feed stock conveyor coupled with the elongate member and operable to deliver a feed stock to a work area of the workpiece, the work area having a preworked shape and a desired post-work shape;

a laser disposed near the insertion end of the elongate member and capable of lasing the workpiece;

wherein the laser interacts with the feed stock in the repair area and both laser and feed stock are manipulated using information from the imager to produce a near net shape repaired component of the workpiece

wherein the laser is configured to emit successive pairings including a first pulse and a second pulse each about 3 ns in duration with an average intensity of about 4 Mega Watts per square centimeter producing a maximum power of about 750 kw, and wherein the laser is configured to provide an interpulse time between the successive pairings of between about 30 ns and about 150 ns.

27. The method of claim 26, wherein the feed stock is one of a powder, a gas, and a wire.

28. The method of claim 26, wherein the workpiece is a gas turbine engine and the component is an airfoil member of the gas turbine engine.

29. An inspection and repair apparatus comprising

a portable imaging and repair system capable of being transported between locations in which an imaging and repair operation is performed, the system including a flexible elongate borescope having an imager capable of capturing electromagnetic emissions from a component to be operated upon and a display in communication with the imager capable of providing information of the electromagnetic emissions to an operator, the system also including a laser capable of changing the state of a material associated with the component;

wherein the laser, display, and imager can be placed in an arrangement that permits the portable imaging and repair system to be readily moved from a first location to a second location; and

the laser is configured to emit successive pairings including a first pulse and a second pulse each about 3 ns in duration, with an interpulse time between the successive pairings of between about 30 ns and about 150 ns, and the laser is configured to move at a speed rate between about 0.2 millimeters per minute and about 1.0 millimeters per minute.

30. The method of claim 29, wherein the arrangement includes having at least one of the laser, display, and imager de-coupled from the portable imaging and repair system.

31. The method of claim 29, wherein the laser is capable of emitting an energy sufficient to remove material from the component.

32. A method comprising

inserting a flexible portion of a borescope inspection device and a laser positioned on a proximate end of the borescope through an inspection port of a gas turbine engine,

directing the laser toward an apparatus to be repaired, and

cutting the apparatus with the laser by (i) emitting a first pulse and a second pulse from the laser, wherein the first pulse and the second pulse each have an average intensity of about 4 Mega Watts per square centimeter producing a maximum power of about 750 kw, and (ii) moving the laser along the apparatus at an average rate of between about 0.2 mm/min and 1.0 mm/min wherein the first pulse has a pulse duration of about 3 nanoseconds and the second pulse has a duration of about 3 nanoseconds;

and wherein a time between the first pulse and the second pulse is between about 30 nanoseconds and about 150 nanoseconds.

33. The method of claim 32, wherein the apparatus comprises an Inconel, titanium, or nickel alloy.