CN112344781A

CN112344781A - Heat sink for induction welding and method of forming a heat sink

Info

Publication number: CN112344781A
Application number: CN202010777930.3A
Authority: CN
Inventors: 罗伯特·A·迪基亚拉; 理查德·W·伯恩斯; 弗兰西斯·J·萨玛洛特·里韦拉; 克里德·欧内斯特·布莱文斯
Original assignee: Boeing Co
Current assignee: Boeing Co
Priority date: 2019-08-06
Filing date: 2020-08-05
Publication date: 2021-02-09

Abstract

The present application relates to a heat sink for induction welding and a method of forming a heat sink. A heat sink for induction welding includes a plurality of tiles, wherein the tiles are electrically non-conductive and have a thickness greater than about 25mm²Thermal diffusivity per second. The joints flexibly connect the tiles together.

Description

Heat sink for induction welding and method of forming a heat sink

Technical Field

The present disclosure relates to induction welding. More particularly, the present disclosure relates to induction welding of cooled thermoplastic composites using flexible heat sinks and/or reducing temperatures away from the weld interface.

Background

Induction welding can be used to fuse or join thermoplastic composite (TPC) parts together. TPC parts typically comprise thermoplastics reinforced with non-plastic materials, such as carbon fibers. TPC parts have high damage, moisture and chemical resistance and do not degrade under high temperature or humidity conditions. Moreover, the TPC components may be remelted, providing benefits in terms of maintenance and end-of-service life recyclability, and reduced handling and storage costs, as compared to other alternatives.

Induction welding involves moving an induction coil along the weld line of a TPC part. The induction coil induces eddy currents in inherently conductive carbon fibers disposed within the TPC component that generate heat and melt the thermoplastic, especially at the weld interface. Compressing the TPC parts together creates a fused or welded joint. The weld joint produced by induction welding is considered to be a unitary piece, so that two or more pieces are one piece.

While induction welding is effective, the induction coil generates heat throughout the TPC parts, not just at the weld joint. For example, the heat in the part of the TPC component near the induction coil is higher than the heat in the welded joint. Accordingly, there is a need in the art for a system and method of induction welding TPC parts that concentrates heat at the weld joint.

Disclosure of Invention

In one example, a heat sink for induction welding is provided. The heat spreader includes a plurality of tiles, wherein the tiles are electrically non-conductive and have a thickness greater than about 25mm²Thermal diffusivity per second. The joints flexibly join the tiles together.

In another example, a method of forming a heat spreader is provided. The method comprises the following steps: spacing a plurality of tiles in a single layer with gaps between the tiles, wherein the tiles are electrically and thermally conductive; and flexibly engaging the tiles.

In another example, a method for forming a heat sink for induction welding is provided. The method includes placing a plurality of tiles in a single layer spaced apart within a frame having a fixture, removing the fixture, and applying a flexible adhesive between the tiles.

The present apparatus, system, and method are also referenced in the following clauses that are not to be confused with the technical solution.

Clause 1. a heat sink (20) for induction welding, the heat sink (20) comprising:

a plurality of tiles (40), wherein the tiles (40) are electrically non-conductive and have a thickness greater than about 25mm²Thermal diffusivity per second; and

joints (42) flexibly connect the tiles (40) together.

Clause 2. the heat sink (20) according to clause 1, wherein the tiles (40) are composed of aluminum nitride.

Clause 3. the heat sink (20) according to clause 1, wherein the tiles (40) are composed of beryllium oxide.

Clause 4. the heat sink (20) according to clause 1, wherein the tiles (40) are arranged in a single layer.

Clause 5. the heat sink (20) of clause 1, wherein the tiles (40) define a gap (44) therebetween, and the knuckle (42) is disposed within the gap (44).

Clause 6. the heat sink (20) of clause 5, wherein the gap (44) is between about 0.005 inches and about 0.1 inches.

Item 7. the heat sink (20) of item 1, wherein the knuckle (42) is constructed of silicone having a long-term degradation temperature of greater than about 400 degrees fahrenheit in vacuum or air.

Clause 8. the heat sink (20) of clause 7, wherein the silicone has an elongation of between 12% and 670%.

Clause 9. the heat sink (20) of clause 7, wherein the tear strength of the silicone is between 31lb/in and 190 lb/in.

Clause 10. the heat sink (20) of clause 1, wherein the tile (40) has a thermal conductivity greater than about 75W/mK.

Clause 11. the heat sink (20) of clause 1, wherein the tiles (40) have a heat capacity greater than about 500J/K/kg.

Clause 12. a portion of an aircraft is manufactured using the heat sink (20) of clause 1.

Clause 13. a method (60) of forming a heat sink (20), the method comprising:

placing a plurality of tiles (40) in a single layer at intervals with gaps (44) between the tiles (40), wherein the tiles (40) are electrically and thermally conductive; and

flexibly joining the tiles (40).

Clause 14. the method of clause 13, wherein flexibly engaging the tiles (40) comprises flexibly engaging the tiles (40) with mechanical hinges (47) disposed within the gaps (44).

Clause 15. the method of clause 13, wherein flexibly engaging the tiles (40) includes flexibly engaging the tiles (40) with a flexible adhesive (45) disposed within the gap (44).

Clause 16. the method of clause 15, wherein flexibly engaging the tile (40) with the flexible adhesive (45) includes injecting the flexible adhesive (45) into the gap (44).

Clause 17. the method of clause 15, further comprising curing the flexible adhesive (45).

Clause 18. the method of clause 13, wherein spacing the tiles (40) comprises spacing the tiles (40) on a backing material (54).

Clause 19. a method (60) of forming a heat sink (20) for induction welding, the method comprising:

placing a plurality of tiles (40) in a single layer at intervals within a frame (56) having a fixture (58);

removing the clamp (58); and

a flexible adhesive (45) is applied between the tiles (40).

Clause 20. the method of clause 19, further comprising priming the tile (40) with a primer.

Clause 21. the method of clause 20, wherein priming the tile (40) comprises priming the tile (40) with a silicone primer.

Clause 22. the method of clause 19, further comprising providing a plurality of electrically and thermally conductive tiles (40) prior to spacing the plurality of tiles (40) within the frame (56).

Clause 23. the method of clause 19, wherein spacing the tiles (40) within the frame (56) includes spacing the tiles (40) on a backing material (54) disposed below the frame (56).

Clause 24. the method of clause 23, wherein spacing the tiles (40) on the backing material (54) comprises adhering the tiles (40) to the backing material (54).

Clause 25. the method of clause 24, further comprising curing the flexible adhesive (45).

Clause 26. the method of clause 25, further comprising removing the backing material (54) after curing the flexible adhesive (45).

Clause 27. a method (80) of induction welding a first carbon fiber thermoplastic composite material (TPC) (12) to a second carbon fiber thermoplastic composite material (TPC) (14) using an induction coil (22), the method comprising:

aligning a first TPC (12) with a second TPC (14) to form a weld interface region (74);

bending the heat sink (20) to a surface (43) of the first TPC (12) between the weld interface region (74) and the induction coil (22); and

the weld interface region (74) is inductively heated with an induction coil (22).

Clause 28. the method of clause 27, wherein the heat sink (20) is electrically non-conductive and thermally conductive.

Clause 29. the method of clause 27, further comprising pressing the first TPC (12) and the second TPC (14) together at the weld interface region (74) while inductively heating the weld interface region (74).

Clause 30. the method of clause 27, further comprising:

inserting a first TPC (12), a second TPC (14), and a heat spreader (20) within a vacuum bag (70); and

the first TPC (12) and the second TPC (14) are consolidated by vacuum compression during or after induction heating the weld interface region (74).

Clause 31. the method of clause 27, further comprising welding a weld interface region (74) along the weld line (26).

Clause 32. the method of clause 27, further comprising absorbing heat from the second TPC (14) with a second heat sink (78).

Clause 33. the method of clause 6, further comprising:

inserting a first TPC (12), a second TPC (14), a heat sink (20), and a second heat sink (78) within a vacuum bag (70); and

the first TPC (12) and the second TPC (14) are compressed under vacuum.

Clause 34. the method of clause 32, further comprising:

the vacuum bag (70) is filled with an inert gas.

Clause 35. the method of clause 27, further comprising adjusting the induction welding in real time based on the sensor feedback.

Clause 36. the method of clause 27, further comprising:

inserting a first TPC (12) and a second TPC (14) between a first plate (91) and a second plate (92); and

the first TPC (12) and the second TPC (14) are compressed between the first plate (91) and the second plate (92) while the weld interface region (74) is inductively heated.

Clause 37. the method of clause 27, wherein bending the heat sink (20) onto the surface (43) of the first TPC (12) includes conforming the heat sink (20) to the surface (43) of the first TPC (12).

Clause 38. the method of clause 27, further comprising cooling the second TPC (14) with a cooler unit (89) disposed adjacent the second TPC (14).

Clause 39. the method of clause 27, further comprising moving the welding interface region (74), the induction coil (22), or both, to weld the welding interface region (74) along the weld line (26).

Clause 40. a system (10) for induction welding a first thermoplastic composite (TPC) (12) to a second thermoplastic composite (TPC) (14), the system (10) comprising:

a heat sink (20) disposed on the first TPC (12), the heat sink (20) having a plurality of tiles (40), the plurality of tiles (40) flexibly joined together by joints (42); and

an induction coil (22) configured to inductively solder the first TPC (12) to the second TPC (14), the induction coil (22) disposed adjacent to the heat sink (20).

Clause 41. the system (10) of clause 40, wherein the heat sink (20) is disposed between the first TPC (12) and the induction coil (22).

Clause 42. the system (10) according to clause 40, further comprising a second heat sink (78) disposed on the second TPC (14).

Clause 43. the system (10) of clause 40, further comprising a vacuum bag (70), wherein the heat sink (20), the first TPC (12), and the second TPC (14) are disposed in the vacuum bag (70).

Clause 44. the system (10) of clause 40, further comprising a first board (91) and a second board (92), and wherein the heat sink (20), the first TPC (12), and the second TPC (14) are disposed between the first board (91) and the second board (92).

Clause 45. the system (10) of clause 40, wherein the tile (40) is electrically non-conductive and has a thickness greater than about 25mm²Thermal diffusivity per second.

Clause 46. the system (10) of clause 45, wherein the tiles (40) are composed of aluminum nitride.

Clause 47. the system (10) of clause 45, wherein the tile (40) is constructed from beryllium oxide.

Clause 48. the system (10) of clause 40, wherein the joint (42) is constructed of silicone having a long-term decomposition temperature greater than about 400 degrees fahrenheit in a vacuum.

Clause 49. the system (10) of clause 40, wherein the joint (42) is a mechanical hinge (47) integrally formed from or bonded to the tile (40).

Clause 50. the system (10) of clause 40, further comprising a tool (16) disposed opposite the induction coil (22), the tool having a cooler unit (89) disposed within the tool (16), the cooler unit (89) adjacent the second TPC (14).

Clause 51. the system (10) of clause 40, further comprising a bellows (39), the bellows (39) disposed adjacent the second TPC (14) for applying a consolidation pressure to the second TPC (14).

Clause 52. a portion (76) of an aircraft is manufactured using the system (10) of clause 40.

Clause 53. a method (80) of induction welding a first carbon fiber thermoplastic composite material (TPC) (12) to a second carbon fiber thermoplastic composite material (TPC) (14) using an induction coil (22), the method comprising:

forming a weld interface region (74) between the first TPC (12) and the second TPC (14);

placing a flexible heat spreader (20) on a surface (43) of the first TPC (12) above the weld interface region (74);

inductively heating the weld interface region (74) with an induction coil (22);

compressing the first TPC (12) and the second TPC (14) together at a weld interface region (74); and

heat is dissipated from a surface (43) of the first TPC (12) using a flexible heat sink (20).

Clause 54. a method of induction welding a first thermoplastic composite (TPC) to a second thermoplastic composite (TPC) using an induction coil, the method comprising:

forming a weld interface region between the first TPC and the second TPC;

cooling the first TPC with a cooling device before being heated by the induction coil; and

after cooling the first TPC, the weld interface region is inductively heated with an induction coil.

Clause 55. the method of clause 54, further comprising setting a target temperature, and wherein cooling the first TPC comprises cooling the first TPC to the target temperature.

Clause 56. the method of clause 55, further comprising monitoring the actual temperature of the first TPC.

Clause 57 the method of clause 56, wherein cooling the first TPC includes cooling the first TPC to a target temperature based on the actual temperature.

Clause 58. the method of clause 56, wherein setting the target temperature comprises:

determining a position of the weld interface region relative to the induction coil; and

the target temperature is set based on the location of the weld interface region.

Clause 59. the method of clause 56, wherein the target temperature is about-100 degrees fahrenheit.

Clause 60. the method of clause 54, further comprising compressing the first TPC and the second TPC together while inductively heating the weld interface region.

Clause 61. the method of clause 54, further comprising:

inserting the first TPC and the second TPC into a vacuum bag; and

the first TPC is vacuum compressed to the second TPC during or after induction heating the weld interface region.

Clause 62. the method of clause 54, further comprising welding the weld interface region along a weld line.

Clause 63. the method of clause 62, wherein the cooling device is coupled to the induction coil.

Clause 64. the method of clause 54, further comprising adjusting the induction heating in real time based on the sensor feedback.

Clause 65. the method of clause 54, further comprising actively cooling the first TPC after inductively heating the weld interface region.

Clause 66. the method of clause 65, further comprising inductively heating the first TPC using a second induction coil after inductively heating the weld interface region using the induction coil.

Clause 67. the method of clause 66, further comprising:

sensing a temperature of the welding interface region after inductively heating the welding interface region using the induction coil; and

the first TPC is cooled using a second cooling device or inductively heated using a second induction coil to control the cooling rate of the first TPC.

Clause 68. a system for induction welding a first carbon fiber thermoplastic composite (TPC) to a second carbon fiber thermoplastic composite (TPC), the system comprising:

an induction coil disposed over the first TPC and movable in a first direction relative to a weld interface region to form a weld between the first TPC and the second TPC; and

a cooling device disposed above the first TPC for cooling the first TPC, the cooling device disposed adjacent to the induction coil in a first direction, the cooling device movable with the induction coil in the first direction to cool the first TPC prior to forming the weld.

Clause 69 the system of clause 68, further comprising a vacuum bag, wherein the first TPC and the second TPC are disposed within the vacuum bag.

Clause 70 the system of clause 68, further comprising a first plate and a second plate, and wherein the first TPC and the second TPC are disposed between the first plate and the second plate.

Clause 71. the system of clause 68, wherein the cooling device is coupled to the induction coil at a fixed distance from the induction coil.

Clause 72 the system of clause 68, wherein the cooling device comprises a plurality of nozzles connected to a coolant source.

Clause 73. the system of clause 72, wherein the coolant source comprises CO₂。

Clause 74. the system of clause 68, further comprising a controller in electronic communication with the induction coil and the cooling device, the controller configured to control movement of the induction coil and the cooling device and a flow rate of coolant from the cooling device.

The system of clause 75, the system of clause 74, further comprising a sensor for sensing a temperature of the first TPC or the second TPC, the sensor in electrical communication with the controller.

The system of clause 75, clause 76, wherein the controller controls the motion of the induction coil and the coolant device and the flow rate of the coolant based on feedback from the sensor to control the cooling rate of the first TPC.

The system of clause 77, the system of clause 68, further comprising a second cooling device disposed adjacent to the induction coil in a second direction opposite the first direction, the second cooling device configured to cool the first TPC after inductively heating the weld interface region with the induction coil.

Clause 78 the system of clause 77, wherein the second cooling device is coupled to the induction coil at a fixed distance from the induction coil.

Clause 79. the system of clause 78, further comprising a second induction coil disposed adjacent to the induction coil in the second direction, the second induction coil configured to heat the first TPC after inductively heating the weld interface region with the induction coil.

Clause 80. the system of clause 79, wherein the second inductive coil is coupled to the inductive coil at a fixed distance from the inductive coil.

Clause 81. an induction welding method using an induction coil, the method comprising:

forming a weld interface region between a first thermoplastic composite (TPC) and a second thermoplastic composite (TPC);

cooling the first TPC with a first cooling device prior to heating by the induction coil;

after cooling the first TPC, performing induction welding on a welding interface area by using an induction coil; and

the first TPC is cooled using a second cooling device or inductively heated using a second induction coil passing after the induction coil to control the cooling rate of the weld interface region.

Clause 82. a method of dissipating heat from a surface of a first thermoplastic composite (TPC) induction welded to a second thermoplastic composite (TPC), the method comprising:

bending the heat spreader during placement to conform to a surface of the first TPC;

cooling the radiator;

applying induction heat to a weld interface region between the first TPC and the second TPC; and

heat is absorbed from the surface of the first TPC via the heat sink.

Clause 83. the method of clause 82, further comprising applying induction heat to the weld interface region along a weld line.

Clause 84. the method of clause 83, wherein cooling the heat sink includes moving a cooling device along the weld line to cool the heat sink prior to inductively heating the weld interface region.

Clause 85. the method of clause 82, wherein bending the heat spreader during placement comprises aligning the heat spreader with the weld interface region along a weld line.

The method of clause 86, the method of clause 82, further comprising bending a second heat spreader to conform to a surface of the second TPC during placement.

Clause 87. the method of clause 86, wherein placing the second heat spreader on the second TPC includes aligning the second heat spreader with the weld interface region along the weld line.

Clause 88 the method of clause 86, further comprising drawing heat from a surface of the second TPC via the second heat sink.

Clause 89. the method of clause 82, wherein bending the heat spreader comprises bending a joint between a plurality of thermally conductive and electrically non-conductive tiles.

Clause 90. the method of clause 82, further comprising setting a target temperature, and wherein cooling the heat sink comprises cooling the heat sink to the target temperature.

Clause 91. the method of clause 90, further comprising monitoring an actual temperature of the heat sink.

Clause 92. the method of clause 91, wherein cooling the heat sink comprises cooling the heat sink to a target temperature based on the actual temperature of the heat sink.

Clause 93. the method of clause 90, wherein setting the target temperature comprises:

determining a position of the heat sink relative to the weld interface region and relative to the induction coil; and

the target temperature is set based on the position of the heat sink.

Clause 94. the method of clause 90, wherein the target temperature is about-100 degrees fahrenheit.

Clause 95. the method of clause 82, further comprising compressing the first TPC and the second TPC together while inductively heating the weld interface region.

Clause 96. the method of clause 82, further comprising:

inserting the first TPC and the second TPC into a vacuum bag; and

Clause 97 the method of clause 82, further comprising cooling the heat sink after induction heating the weld interface region.

Clause 98. the method of clause 97, further comprising inductively heating the first TPC using a second induction coil after inductively heating the weld interface region using a first induction coil.

Clause 99. the method of clause 98, further comprising:

sensing a temperature of the welding interface region after inductively heating the welding interface region using the first induction coil; and

the first TPC is cooled using a second induction coil or inductively heated to control the cooling rate of the first TPC.

Clause 100. a system for induction welding a first thermoplastic composite (TPC) to a second thermoplastic composite (TPC), the system comprising:

a heat sink disposed on the first TPC, the heat sink having a plurality of tiles flexibly joined together by a joint;

an induction coil disposed above the heat sink and movable in a first direction relative to the weld interface region to form a weld at the weld interface region between the first TPC and the second TPC; and

a cooling device disposed above the heat sink to cool the heat sink, the cooling device disposed adjacent to the induction coil in a first direction, the cooling device movable in the first direction to cool the heat sink prior to forming the weld.

Clause 101 the system of clause 100, further comprising a vacuum bag, wherein the first TPC, the second TPC and the heat spreader are disposed within the vacuum bag.

Clause 102 the system of clause 101, further comprising a second heat sink disposed on the second TPC.

Clause 103. the system of clause 102, wherein the second heat sink is disposed within the vacuum bag.

Clause 104 the system of clause 100, further comprising a tool disposed opposite the induction coil, the tool having a cooler unit disposed within the tool, the cooler unit adjacent the second TPC.

Clause 105. the system of clause 100, wherein the cooling device is connected to the induction coil at a fixed distance from the induction coil.

Clause 106 the system of clause 100, wherein the cooling device comprises a plurality of nozzles connected to a coolant source.

Clause 107. the system of clause 106, wherein the coolant source comprises a CO₂。

Clause 108. the system of clause 100, further comprising a controller in electronic communication with the induction coil and the cooling device, the controller configured to control movement of the induction coil and the cooling device and a flow rate of coolant from the cooling device.

Clause 109. the system of clause 108, further comprising a sensor for sensing a temperature of the heat sink, the sensor in electronic communication with the controller.

Clause 110 the system of clause 109, wherein the controller controls the motion of the induction coil and the cooling device and the flow rate of the coolant based on feedback from the sensor to control the cooling rate of the first TPC.

Clause 111. the system of clause 100, further comprising a second cooling device disposed adjacent to the induction coil in a second direction opposite the first direction, the second cooling device configured to cool the heat sink after inductively heating the weld interface region with the induction coil.

Clause 112. the system of clause 111, wherein the second cooling device is coupled to the induction coil at a fixed distance from the induction coil.

Clause 113 the system of clause 111, further comprising a second induction coil disposed adjacent to the induction coil in the second direction, the second induction coil configured to heat the first TPC after inductively heating the weld interface region with the induction coil.

Clause 114. the system of clause 113, wherein the second inductive coil is coupled to the inductive coil at a fixed distance from the inductive coil.

Clause 115. a method of dissipating heat from a surface of a first thermoplastic composite (TPC) induction welded to a second thermoplastic composite (TPC), the method comprising:

bending the heat spreader to conform to a surface of the first TPC;

cooling the heat sink prior to induction heating;

applying induction heat to a weld interface region between the first TPC and the second TPC;

absorbing heat from a surface of the first TPC via a heat sink; and

the radiator is cooled after induction heating.

The features, functions, and advantages that have been discussed can be achieved independently in various aspects or may be combined in yet other aspects further details of which can be seen with reference to the following description and drawings.

Drawings

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

FIG. 1A is a perspective view of a system for induction welding according to an exemplary aspect;

FIG. 1B is a perspective view of a variation of a system for induction welding according to an exemplary aspect;

FIG. 2A is an enlarged portion of the heat sink shown by arrows 2-2 in FIG. 1A, according to an exemplary aspect;

FIG. 2B is a perspective view of a heat sink shown on an exemplary curved surface, according to an exemplary aspect;

FIG. 3 is a perspective view of a heat sink manufacturing system for manufacturing the heat sink of FIG. 2A, according to an exemplary aspect;

FIG. 4 is an exemplary process flow diagram illustrating a method of manufacturing the heat spreader of FIG. 2A using the heat spreader manufacturing system of FIG. 3, according to an exemplary aspect;

FIG. 5A is an exemplary perspective view of a portion of a heat sink having a mechanical hinge according to an exemplary aspect;

FIG. 5B is a cross-section of the heat sink viewed in the direction of arrows 5A-5A in FIG. 5A, according to an exemplary aspect;

FIG. 6 is an enlarged partial cross-sectional view of a stack of the system as viewed in the direction of arrows 6-6 in FIG. 1A, according to an exemplary aspect;

FIG. 7 is an exemplary process flow diagram illustrating an induction welding method according to an exemplary aspect;

FIG. 8 is an enlarged partial cross-sectional view of another stack of the system as viewed in the direction of arrows 6-6 in FIG. 1A, according to an exemplary aspect;

FIG. 9 is an enlarged partial cross-sectional view of another stack of the system as viewed in the direction of arrows 6-6 in FIG. 1A, according to an exemplary aspect;

FIG. 10 is an enlarged partial cross-sectional view of another stack of the system as viewed in the direction of arrows 6-6 in FIG. 1A, according to an exemplary aspect;

FIG. 11 is an enlarged partial cross-sectional view of another stack of the system as viewed in the direction of arrows 6-6 in FIG. 1A, according to an exemplary aspect;

FIG. 12 is an enlarged partial cross-sectional view of another stack of the system as viewed in the direction of arrows 6-6 in FIG. 1A, according to an exemplary aspect;

FIG. 13 is an exemplary process flow diagram of induction welding according to an exemplary aspect;

FIG. 14 is another exemplary process flow diagram of induction welding according to an exemplary aspect;

FIG. 15 is an enlarged partial cross-sectional view of another stack of the system as viewed in the direction of arrows 6-6 in FIG. 1A, according to an exemplary aspect;

FIG. 16 is an enlarged partial cross-sectional view of another stack of the system as viewed in the direction of arrows 6-6 in FIG. 1A, according to an exemplary aspect;

FIG. 17 is an exemplary process flow diagram of induction welding according to an exemplary aspect;

FIG. 18 is another exemplary process flow diagram of induction welding according to an exemplary aspect;

FIG. 19 is a perspective view of another example of a heat sink with liquid cooling according to an exemplary aspect;

FIG. 20 is an exemplary process flow diagram illustrating a method of manufacturing a heat sink having the liquid cooling of FIG. 19 using the heat sink manufacturing system of FIG. 3, according to an exemplary aspect;

FIG. 21 is a perspective view of a heat sink manufacturing system for manufacturing a heat sink having the liquid-cooled heat sink of FIG. 19, according to an exemplary aspect;

FIG. 22 is an enlarged cross-section of another stack of the system viewed in the direction of arrows 6-6 in FIG. 1A using a heat sink with liquid cooling, according to an exemplary aspect;

FIG. 23 is a perspective view of another example of a heat sink with liquid cooling according to an exemplary aspect;

FIG. 24 is a perspective view of another example of a heat sink with liquid cooling according to an exemplary aspect;

FIG. 25 is a top view of another example of a heat sink used during induction welding according to an exemplary aspect;

FIG. 26 is a cross-sectional view of the heat sink looking in the direction of arrows 26-26 in FIG. 25, according to an exemplary aspect;

FIG. 27 is a cross-sectional view of a variation of the heat sink shown in FIG. 25, according to an exemplary aspect;

FIG. 28 is a schematic view of an induction welding system using the heat sink shown in FIG. 25, according to an exemplary aspect;

FIG. 29 is a schematic view of an induction welding system using the heat sink shown in FIG. 25, according to an exemplary aspect;

FIG. 30 is a flow chart of an aircraft production and service method; and

fig. 31 is a block diagram of an aircraft.

Detailed Description

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.

Referring to fig. 1A, a schematic diagram of a system 10 for induction welding a first thermoplastic composite (TPC)12 to a second TPC14 is shown. As will be described below, the system 10 may be used in the context of aircraft manufacturing and service. For example, the system 10 may be used in the manufacture of components and subassemblies for aircraft, including interior manufacturing, acoustic panels, system integration of aircraft, airframe manufacturing, and routine maintenance and service of aircraft. However, the system 10 may be used in a variety of other industries, including the automotive, construction, sporting goods, and general transportation industries, to name a few. The first TPC12 and the second TPC14 are shown as flat plates. However, it should be understood that the first TPC12 and the second TPC14 may be contoured, curved, or otherwise non-planar without departing from the scope of the present disclosure, as described with respect to fig. 2A below. Additionally, the first TPC12 and the second TPC14 may be comprised of various thermoplastics reinforced with various conductive materials. In one example, the thermoplastic is selected from the group consisting of semi-crystalline thermoplastics and amorphous thermoplastics. Semi-crystalline thermoplastics may include polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyether ketone (PEKK), and polyaryl ketone (PAEK). The amorphous thermoplastic may include Polyetherimide (PEI). Semi-crystalline thermoplastics have high consolidation temperatures and good mechanical properties relative to conventional thermoplastics. Amorphous thermoplastics exhibit a gradual softening upon heating relative to conventional thermoplastics, and the material has good elongation, toughness and impact resistance. Semi-crystalline thermoplastics contain tightly folded chain (crystallite) regions that link together and exhibit a distinct melting point upon heating when the crystalline regions begin to dissolve. As the polymer approaches its melting point, the lattice breaks and the molecules are free to rotate and translate. During slow cooling, semi-crystalline thermoplastics nucleate and grow crystalline domains that provide greater strength, stiffness, solvent resistance, and temperature stability relative to an amorphous structure. If a semi-crystalline thermoplastic cools too quickly, it may form an amorphous structure.

In another example, the electrically conductive material comprises carbon fiber. The carbon fibers may be oriented within the thermoplastic in various configurations (not shown), which in turn affects the degree of heating during induction welding. For example, the carbon fibers may be oriented at 0 and 90 degrees, +/-45 degrees or +/-60 degrees in a cross-hatch pattern, to name a few. The carbon fibers may be unidirectional or woven together. Each such configuration may affect the degree of heating in the first TPC12 and the second TPC14 under a given magnetic field. It should be understood that although two TPC portions are shown, any number of stacked TPC portions may be employed.

The system 10 generally includes a tool base 16, an induction welder 18, and a heat sink 20. The tool base 16 supports the first TPC12 and the second TPC14 thereon. In the example provided, the tool base 16 is flat. However, it should be understood that the tool base 16 may have various other shapes to support the first TPC12 and the second TPC 14.

The induction welder 18 is configured to inductively heat the first TPC12 and the second TPC14 and may take various forms without departing from the scope of the present disclosure. In the example provided, the induction welder 18 includes an induction coil 22 mounted to a robotic arm 24. The induction coil 22 may also be mounted to any other suitable robotic arm 24. In another aspect, the induction coil 22 may be stationary and the first TPC12 and the second TPC14 move relative to the induction coil 22. Accordingly, the induction coil 22 may move relative to the first TPC12 and the second TPC14, and the first TPC12 and the second TPC14 may move relative to the induction coil 22. In another example, the induction coil 22 and both the first TPC12 and the second TPC14 may be movable. The induction coil 22 generates a magnetic field 25 to induce eddy currents in the carbon fibers of the first TPC12 and the second TPC 14. The robot arm 24 moves the induction coil 22 along the weld line 26 in a first direction 26A. Thus, the weld line 26 is the area where the first TPC12 and the second TPC14 will be welded together. The weld line 26 may be straight or curved or any other pattern. The first roller 28A and the second roller 28B are arranged near the induction coil 22. The first roller 28A is arranged on the front side 22A of the induction coil 22. The second roller 28B is arranged on the rear side 22B of the induction coil 22. The first roller 28A and the second roller 28B apply consolidation pressure to the first TPC12 and the second TPC14 during induction welding, as described below. In the example provided, the first roller 28A and the second roller 28B are connected to the induction coil 22, but it should be understood that the first roller 28A and the second roller 28B may be separated without departing from the scope of the present disclosure. The first roller 28A and the second roller 28B may articulate to allow the first roller 28A and the second roller 28B to move over the contoured surface while maintaining the consolidation pressure against the first TPC 12. Further, consolidation pressure may be applied during or after induction welding when the induction coil 22 is moved in the first direction 26A or an opposite direction. In addition, other methods may be employed to apply the consolidation pressure, as described below with reference to FIG. 1B.

The induction welder 18 is in electrical communication with a controller 30. The controller 30 is operable to control the amount of current provided to the induction coil 22, which in turn controls the magnetic field strength and thus the heating of the first TPC12 and the second TPC 14. The controller 30 is also operable to control the movement of the robot arm 24 or the induction coil 22 relative to the weld line 26. The controller 30 is a non-general purpose electronic control device having a preprogrammed digital computer or processor 32, a memory or non-transitory computer readable medium 34 for storing data, such as control logic, software applications, instructions, computer code, data, look-up tables, and the like, and input/output ports 36. Non-transitory computer-readable medium 34 includes any type of medium capable of being accessed by a computer, such as Read Only Memory (ROM), Random Access Memory (RAM), a hard disk drive, a Compact Disc (CD), a Digital Video Disc (DVD), or any other type of memory. A "non-transitory" computer-readable medium does not include a wired, wireless, optical, or other communication link that transmits transitory electrical or other signals. Non-transitory computer-readable media include media that can permanently store data as well as media that can store data and subsequently overwrite, such as a rewritable optical disk or an erasable storage device. Computer code includes any type of program code, including source code, object code, and executable code. The processor 32 is configured to execute code or instructions.

The system 10 may further include a plurality of sensors 38 in electronic communication with the controller 30. The sensor 38 is configured to detect or sense a condition of the first TPC12 and/or the second TPC14 during induction welding in order to provide real-time feedback to the controller 30. For example, the sensor 38 may be an infrared temperature sensor configured to detect the temperature of the first TPC12 and/or the second TPC 14. Alternatively, or in addition, the sensor 38 may be an electromagnetic field sensor configured to detect the magnetic field 25 generated by the induction coil 22. Sensor 38 may be used by controller 30 for feedback control of the motion of induction coil 22, as described below.

Fig. 1B illustrates an alternative arrangement of the system 10 according to the principles of the present disclosure. The arrangement shown in fig. 1B is similar to that shown in fig. 1A, however,

rollers

28A and 28B have been removed and second TPC14 is shown as having an "L" shaped cross section. Other possible cross-sections of the second TPC14 and/or the first TPC12 include at least "J", "I", "T", "Z" and/or "hat" cross-sections. Consolidation pressure is provided by bellows 39 disposed below the second TPC14 along weld line 26. Expansion of the bellows 39 applying consolidation pressure to the second TPC14 may be controlled by the controller 30.

Returning to fig. 1A, the heat sink 20 is configured to absorb and dissipate heat from the first TPC 12. As described below, the heat sink 20 is disposed between the first TPC12 and the induction coil 22. Fig. 2A shows an enlarged portion of the heat sink 20 of fig. 1A. Referring to fig. 2A, the heat sink 20 includes a plurality of tiles 40 connected by joints 42. The joints 42 are disposed between the tiles 40. The tiles 40 are made of a material that is electrically and thermally conductive. Thus, when under the induction coil 22 (fig. 1A), the tiles 40 are not heated by the magnetic field 25 but absorb heat from the first TPC 12. In one example, the thermal diffusivity of tiles 40 is greater than about 25mm²Per second, preferably greater than about 70mm²In seconds. In this case, the term "about" is known to the person skilled in the art. Alternatively, the term "about" can be understood to mean plus or minus 5mm²In seconds. In another example, the tiles 40 have a thermal conductivity greater than about 75W/mK, preferably greater than about 150W/mK. In this case, the term "about" is known to the person skilled in the art. Alternatively, the term "about" can be understood to mean plus or minus 10W/mK. In another example, tiles 40 have a heat capacity greater than about 500J/K/kg and preferably greater than about 700J/K/kg. In this case, the term "about" is known to the person skilled in the art. Alternatively, the term "about" can be understood to mean plus or minus 50J/K/kg. In one example, tiles 40 are composed of aluminum nitride. The aluminum nitride has low residual carbon in the material matrix to ensure that the induction coil 22 will not couple with the carbon in the tile 40 during induction welding of the first TPC12 and will not pass throughThe tiles 40 are intentionally heated. In another example, the tiles 40 are constructed of beryllium oxide. In another example, tiles 40 are composed of cubic boron nitride (c-BN) or hexagonal boron nitride (h-BN).

The joints 42 flexibly hold the tiles 40 together and provide flexibility to the heat sink 20, allowing the heat sink 20 to conform to the contour of the first TPC 12. For example, fig. 2B shows the heat spreader 20 on the contoured surface 43 of the first TPC 12. In the example provided, the contoured surface 43 is curved. The heat sink 20 pivots at the joints 42 to maintain contact between the tiles 40 and the contoured surface 43. The knuckle 42 may be comprised of either a flexible adhesive 45 as shown in fig. 2A and 2B or a mechanical hinge 47 as shown in fig. 5A. Referring to fig. 2A, the flexible adhesive 45 provides flexibility to the heat spreader 20 and does not melt during heating of the tile 40 during induction welding. Preferably, a minimum amount of flexible adhesive 45 is used to hold the tiles 40 together, thereby increasing the heat dissipation capacity of the heat sink 20. Thus, in one example, the long term degradation temperature of the flexible adhesive 45 in air is greater than about 570 degrees Fahrenheit. In this case, the term "about" is known to the person skilled in the art. Alternatively, the term "about" may be understood to mean plus or minus 25 degrees Fahrenheit. In another example, the flexible adhesive 45 has an elongation between 120% and 670%. In another example, the flexible adhesive 45 has a tensile strength between 690psi and 1035 psi. In another example, the flexible adhesive 45 has a tear strength (die B) of between 31lb/in and 190 lb/in. Thus, in one example, the flexible adhesive 45 is composed of silicone. An example of a suitable silicone resin is 3145RTV from Dow Corning. However, other silicones may be used.

The tiles 40 are arranged in a single layer in a parquet or geometric pattern. Thus, each tile 40 defines a gap 44 therebetween, and the knuckle 42 is disposed within the gap 44. The tiles 40 are arranged, sized, and shaped to help facilitate contour adaptation to the contoured surface 43 (fig. 2B) of the first TPC 12. In one example, the width 49 of the gap 44 is between about 0.005 inches and about 0.1 inches, preferably about 0.040 inches. In this case, the term "about" is known to the person skilled in the art. Alternatively, the term "about" can be understood to mean plus or minus 0.005 inches. Although tiles 40 are illustrated as squares, which maximize the surface area of tiles 40 relative to joints 42, tiles 40 may have various other shapes without departing from the scope of the present disclosure. For example, the tiles 40 may have straight or curved edges and have three or more sides to help accommodate the profile of the first TPC12 and/or the shape of the weld. The heat sink 20 is sized to preferably cover at least the bond wires 26 (fig. 1A), or, as in the present example, the entire first TPC12 (fig. 1A).

Fig. 3 illustrates a heat sink manufacturing system 50 for manufacturing the heat sink 20 (fig. 2A). The heat sink manufacturing system 50 includes a substrate 52 supporting a backing material 54. In one example, the backing material 54 is a double-sided adhesive tape that is adhered to the substrate 52. In another example, the backing material 54 is a glass cloth tape. In yet another example, the backing material 54 is polytetrafluoroethylene-coated glass fibers sprayed with a binder having a glass cloth primer. In this configuration, curing occurs on both sides of the backing material 54. A frame 56 having a clamp 58 is disposed on the backing material 54. In one aspect, the clip 58 is constructed from a single wire 59 that is braided together. The jig 58 is sized to create the gap 44 (fig. 2A) in the heat sink 20. The frame 56 and the clip 58 are removable from the backing material 54.

Fig. 4 illustrates a flow chart of a method 60 for creating the heat sink 20 of fig. 2A using the heat sink manufacturing system 50 of fig. 3. The method 60 begins at block 60A, where the tiles 40 may be primed with a primer prior to placement on the backing material 54 in block 60A. In one example, the primer is a silicone primer. At block 60B, tiles 40 are arranged in a pattern within fixture 58. For example, tiles 40 are placed on backing material 54 between clips 58. The backing material 54 holds the tiles 40 in place while the clips 58 space the tiles 40 apart. Thus, the pattern is defined by the jig 58. Once tiles 40 are placed in block 60B, frame 56 and clamps 58 are removed in block 60C, leaving gaps 44 between tiles 40.

Next, at block 60D, tiles 40 are flexibly joined together with joints 42. In the example provided, the joints 42 are applied within the gaps 44 between the tiles 40. The joint 42 is then preferably cured for a period of time at block 60E. Once cured, the assembled heat spreader 20 may be removed from the backing material 54 at block 60F.

Fig. 5A shows a portion of the heat sink 20, which employs an example of a mechanical hinge 47 that flexibly connects the tiles 40. The first tile 40A includes tabs 65 extending from a plurality of sides 66 of the first tile 40A. The tab 65 may be integrally formed with the first tile 40A or joined to the first tile 40A. An adjacent second tile 40B includes slots 67 disposed in a plurality of sides 68 of the second tile 40B. It is understood that, as described above, the first tile 40A and the second tile 40B may have three or more sides without departing from the scope of this disclosure. Referring to fig. 5B, a first tile 40A is connected to a second tile 40B by inserting tab 65 into slot 67. The tab 65 and slot 67 are configured to allow the first tile 40A to pivot relative to the second tile 40B. For example, the first tile 40A may pivot +/- θ degrees relative to the second tile 40B. In one example, the flexible adhesive 45 (fig. 2A) may be disposed within the mechanical hinge 47. The

tiles

40A, 40B are arranged in a single layer to form a parquet pattern. Thus, by alternately connecting the plurality of first tiles 40A to the plurality of second tiles 40B, the heat sink 20 can be manufactured to any size or shape.

Returning to fig. 1A, system 10 may further include a vacuum bag 70. The vacuum bag 70 is connected to a vacuum source 72. Vacuum source 72 is configured to apply a vacuum to vacuum bag 70. The vacuum source 72 is preferably controlled by the controller 30. The first TPC12, the second TPC14 and the heat spreader 20 are all arranged within a vacuum bag 70. By removing air from the vacuum bag 70, the flexible adhesive 45 of the knuckle 42 (fig. 2A) of the heat spreader 20 is able to withstand higher temperatures prior to degradation than an air/oxygen environment. Alternatively, vacuum source 72 may be replaced with a pump (not shown) that fills vacuum bag 70 with an inert gas such as nitrogen. The inert gas displaces air within the vacuum bag 70 and also subjects the flexible adhesive 45 of the knuckle 42 (fig. 2A) of the heat sink 20 to a higher temperature prior to degradation than an air/oxygen environment. The vacuum bag 70 is also configured to apply consolidation pressure via vacuum compression onto the first TPC12 and the second TPC 14.

Fig. 6 shows a cross section of the stack showing a side view of the first TPC12, the second TPC14, the heat spreader 20 and the vacuum bag 70 on the tool base 16 and the induction coil 22. The first TPC12 is disposed on top of the second TPC 14. A weld interface region 74 is defined along the weld line 26 (fig. 1A) between the first TPC12 and the second TPC 14. The heat sink 20 is disposed on top of the first TPC12 between the induction coil 22 and the first TPC 12. The induction coil 22 is spaced apart from the first TPC12 by a distance "d". In one example, the distance d is about 8 mm. The thickness "t" of the heat sink 20 is less than the distance d. In one example, the thickness t is about 4 mm. In yet another example, the heat sink 20 is cooled before it is placed on the first TPC 12. The first roller 28A and the second roller 28B apply consolidation pressure on the first TPC12 through the vacuum bag 70 and the heat spreader 20, thereby compressing the first TPC12 onto the second TPC 14. In one example, the first roller 28A and the second roller 28B maintain the induction coil 22 at a height above the first TPC 12.

During induction welding, the controller 30 (fig. 1A) commands a current through the induction coil 22 to generate the magnetic field 25. The magnetic field 25 heats the carbon fibers within the first TPC12 and the second TPC 14. The first TPC12, being closer to the induction coil 22, heats up to a greater extent than it heats up closer to the weld interface region 74. However, the heat sink 20 absorbs and dissipates heat within the portion 76 of the first TPC 12. The heat generated by the induction welder 18 is concentrated at the weld interface region 74. When the thermoplastic at the weld interface region 74 is heated above the melting point or consolidation temperature of the material, the first roller 28A and the second roller 28B exert consolidation pressure on the first TPC12 to merge the first TPC12 with the second TPC14 at the weld interface region 74, resulting in a uniform melt bond upon cooling. In one example, the weld interface region 74 is heated to about 20 degrees above the consolidation temperature. The controller 30 then commands the robot arm 24 to move along the weld line 26 (fig. 1A) in the first direction 26A (fig. 1A) to weld the first TPC12 portion to the second TPC 14. Feedback from the sensor 38 (fig. 1A) can be used to command different currents to the induction coil 22 to adjust the heating value in real time. The heat sink 20 also allows the first TPC12 to facilitate inductionThe rate at which the semicrystalline thermoplastic crystallizes in the weld interface region 74 after welding cools, thereby increasing the amount of crystallization of the semicrystalline thermoplastic. For example, during induction welding, the heat sink 20 absorbs heat in the tiles 40. After induction welding, the heat absorbed in the tiles 40 that is not dissipated to the atmosphere is absorbed back into the first TPC12, allowing the first TPC12 to cool at a certain rate that increases the amount of crystallization. For example, the best cooling rate for PEEK is 0.2-20F/min, which will result in a crystal content of 25-35%. The crystallization rate is also dependent on the particular annealing temperature, with the peak rate being about at the glass transition temperature (T)_g) And melting temperature (T)_m) The midpoint therebetween.

Referring to fig. 7, with continued reference to fig. 1A and 6, a flow diagram of a method 80 of inductively welding a first TPC12 to a second TPC14 using the system 10 is shown. The method 80 begins at block 81 by aligning the first TPC12 with the second TPC14 to form the weld interface region 74. Next, at block 82, the heat sink 20 is placed on the first TPC 12. As noted above, the heat sink 20 preferably covers the weld interface region 74 at least along the weld line 26. Because the heat sink 20 is flexible, the heat sink 20 conforms to the surface profile of the first TPC12, whether planar or non-planar, as shown in fig. 2B. In the example provided, the first TPC12, the second TPC14 and the heat spreader 20 are all placed within a vacuum bag 70. Vacuum source 72 may then apply a vacuum to vacuum bag 70. The vacuum bag 70 exerts consolidation forces of up to 1 atmosphere on the first TPC12 and the second TPC 14. Alternatively, an inert gas may be pumped into the vacuum bag 70.

At block 83, the weld interface region 74 is inductively heated by the induction coil 22. At block 84, heat generated in the portion 76 closest to the induction coil 22 is absorbed and dissipated by the heat sink 20, thereby cooling the portion 76. At block 85, the first roller 28A and the second roller 28B apply consolidation pressure on the first TPC12 to merge the first TPC12 with the second TPC14 at the weld interface region 74 to produce a uniform melt bond upon cooling. It should be appreciated that blocks 83, 84, and 85 may occur simultaneously. In another example, bellows 39 (fig. 1B) or other device may exert consolidation pressure on the second TPC 14. At block 86, the weld interface region 74 is induction welded along the weld line 26 by moving the induction coil 22 along the weld line 26 to weld the first TPC12 portion to the second TPC 14. Alternatively, the weld interface region 74 may be movable relative to the induction coil 22. At block 87, the induction welding process is adjusted in real time using feedback from the sensors 38. For example, the controller 30 may command different currents to the induction coil 22 to adjust the heat in real time, command the speed between the induction coil 22 and the weld interface region 74, and so forth.

Fig. 8 shows a cross-section of a stack of the first TPC12, the second TPC14, the heat spreader 20 and the vacuum bag 70 on the tool base 16 in a side view of the induction coil 22. However, a second heat sink 78 is included. The second heat sink 78 is substantially similar to the heat sink 20.

The first TPC12 is disposed on top of the second TPC 14. The heat sink 20 is disposed on top of the first TPC12 between the induction coil 22 and the first TPC 12. A second heat sink 78 is disposed between the tool base 16 and the second TPC 14. Further, a second heat sink 78 is disposed within the vacuum bag 70. As noted above, during induction welding, it is desirable to concentrate the heat at the weld interface region 74 and minimize the heat at other areas of the first TPC12 and the second TPC 14. However, during the induction welding process, heat is generated in the first TPC12, the weld interface region 74, and the second TPC 14. The heat sink 20 absorbs and dissipates heat generated in the portion 76 in the first TPC12 and the second TPC 14. The second heat sink 78 absorbs and dissipates heat generated in the portion 88 of the second TPC14 adjacent the second heat sink 78. Thus, heat is concentrated along the weld interface region 74 rather than the portion 76 of the first TPC12 and not the portion 88 of the second TPC 14.

Fig. 9 illustrates an enlarged cross-section of the system 10 showing another example of a stack of the first TPC12, the second TPC14, the heat spreader 20 and the vacuum bag 70 on the tool base 16. However, the base 16 includes a cooler unit 89 embedded therein. Alternatively, the cooler unit 89 may be provided on a surface of the tool base 16 (not shown). The chiller unit 89 is connected to a coolant source 90. The cooler unit 89 may include piping within the tool base 16 and the coolant source 90 may include a fluid heat exchanger and a pump (not shown). The coolant source 90 is in electrical communication with the controller 30 (fig. 1A).

The first TPC12 is disposed on top of the second TPC 14. The heat sink 20 is disposed on top of the first TPC12 between the induction coil 22 and the first TPC 12. The second TPC14 is located proximate to a cooler unit 89 within the tool base 16. As noted above, during induction welding, it is desirable to concentrate heat at the weld interface region 74. The cooler unit 89 acts as a heat exchanger for the portion 88 of the second TPC14 adjacent the cooler unit 89 and reduces the heat in the second TPC14, while the heat sink 20 absorbs and dissipates the heat in the first TPC 12. Thus, heat is concentrated along the weld interface region 74, rather than the portion 76 of the first TPC12 and the portion 88 of the second TPC 14.

Fig. 10 shows a cross section of a stack of the first TPC12, the second TPC14, the heat sink 20 and the second heat sink 78 on the tool base 16 in a side view of the induction coil 22. The vacuum bag 70 is replaced by a first plate 91 and a second plate 92.

The first TPC12 is disposed on top of the second TPC 14. The heat sink 20 is disposed on top of the first TPC12 between the induction coil 22 and the first TPC 12. The second heat sink 78 is adjacent the second TPC 14. The first TPC12, the second TPC14, the heat sink 20, and the second heat sink 78 are all sandwiched between a first board 91 and a second board 92. The first board 91 and the second board 92 provide stability for the lay down by preventing the first TPC12, the second TPC14, the heat sink 20 and the second heat sink 78 from moving relative to each other. As described above, the first roller 28A and the second roller 28B contact the first plate 91 and provide consolidation pressure during induction welding.

Fig. 11 illustrates an enlarged partial cross-section of the system 10 showing another example of the first TPC12, the second TPC14, and the vacuum bag 70 on the tool base 16 without the use of a heat sink. However, the induction welder 18 has a cooling device 93. The cooling device 93 is disposed adjacent to the induction coil 22 in the first direction 26A (fig. 1A). The cooling device 93 is connected to the induction coil 22 through a member 94 so as to fix the distance between the induction coil 22 and the cooling device 93. However, it should be understood that the cooling apparatus 93 may be separate without departing from the scope of the present disclosure. The cooling apparatus 93 includes a plurality of nozzles 96 configured to discharge a coolant. The cooling device 93 is connected to a coolant source 98 and the controller 30. In one example, the coolant used is CO₂A gas. However, other coolants may be used. As mentioned above, no heat sink is employed in this example.

During induction welding, the cooling apparatus 93 cools the first TPC12 prior to the induction coil 22 by discharging coolant onto the first TPC 12. In one example, the cooling device 93 is configured to cool the first TPC12 to approximately-100 degrees fahrenheit. In this case, the term "about" is known to the person skilled in the art. Alternatively, the term "about" may be understood to mean plus or minus 25 degrees Fahrenheit. Cooling the first TPC12 creates a thermal gradient and maintains the temperature of the portion 76 of the first TPC12 below the consolidation temperature during induction welding. The thermal gradient is the temperature difference at a portion 76 of the first TPC12 adjacent the induction coil 22 relative to the temperature at the weld interface region 74. The thermal gradient may be determined by the number of nozzles 96, the coolant flow rate from the nozzles 96, the distance from the cooling device 93 to the induction coil 22, and the strength of the magnetic field generated by the induction coil 22, as well as the thickness of the first TPC12 and the second TPC14, and the carbon fiber orientation. In addition, controller 30 may adjust the amount of cooling and heating in real time based on feedback received from sensors 38 (FIG. 1A).

Fig. 12 shows a cross-section of a stack of the first TPC12, the second TPC14, the vacuum bag 70 on the tool base 16 without the use of a heat sink in a side view of the induction coil 22. However, the induction welder 18 includes a second cooling apparatus 100 and a second induction coil 102. The second cooling device 100 and the second induction coil 102 are each disposed adjacent to the induction coil 22 in a direction opposite to the first direction 26A (fig. 1A). Thus, the second cooling device 100 and the second induction coil 102 are arranged opposite to the cooling device 93. The second cooling device 100 and the second induction coil 102 are connected to the induction coil 22 through a member 104 so as to fix a distance between the induction coil 22 and the second cooling device 100 and the second induction coil 102. However, it should be understood that the second cooling device 100 and/or the second induction coil 102 may be separate without departing from the scope of the present disclosure. The second cooling apparatus 100 includes a plurality of nozzles 106 configured to discharge a coolant. Second cooling apparatus 100 is connected to coolant source 98 and controller 30. Second induction coil 102 is similar to induction coil 22 and is controlled by controller 30. As noted above, no heat sink is used in this example.

During induction welding, the cooling apparatus 93 cools the first TPC12 prior to the induction coil 22 by discharging coolant onto the first TPC12, as described above. As the induction welder 18 moves along the weld line 26 (fig. 1A), the induction coil 22 melts the weld interface region 74 and the first TPC12 merges with the second TPC14 under consolidation pressure from the first roller 28A and the second roller 28B. To control the cooling of the weld interface region 74, the controller 30 uses a second cooling apparatus 100 and a second induction coil 102 to heat and cool the combined weld interface region 74. The cooling rate at the weld interface region 74 is controlled by controlling the amount of cooling and heating in real time by the controller 30 based on feedback received from the sensor 38 (fig. 1A). The cooling rate may be controlled to maximize crystallization of the thermoplastic at the weld interface region 74, thereby improving strength.

Referring to fig. 13, with continued reference to fig. 1A and 11, a flow diagram of a method 110 for induction welding a first TPC12 to a second TPC14 using a system 10 having a cooling device 93 is shown. The method 110 begins at block 112 by aligning the first TPC12 with the second TPC14 to form the weld interface region 74. In the example provided, the first TPC12 and the second TPC14 are all placed within a vacuum bag 70. A vacuum may then be applied to vacuum bag 70 by vacuum source 72. Alternatively, an inert gas may be pumped into the vacuum bag 70.

Next, at block 114, the first TPC12 is cooled using the cooling apparatus 93. In one example, controller 30 sets a target temperature at weld interface region 74 or portion 76. Then, during cooling by the cooling apparatus 93, the controller 30 monitors the actual temperature at the weld interface region 74 or portion 76 using the sensor 38. The controller 30 then controls the amount of cooling provided by the cooling device 93 to match the actual temperature with the target temperature. The target temperature may be set using a look-up table, or may be calculated using specific factors given to achieve a specific thermal gradient. For example, setting the target temperature may determine the position of the weld interface region 74 relative to the induction coil 22 and set the target temperature based on the position of the weld interface region 74. Other factors may include the number of nozzles 96, the coolant flow rate from the nozzles 96, the distance from the cooling device 93 to the induction coil 22, the strength of the magnetic field generated by the induction coil 22 and the thickness and carbon fiber orientation of the first and

second TPCs

12, 14, and the speed at which the induction coil 22 moves relative to the weld interface region 74 or the speed at which the weld interface region 74 moves relative to the induction coil 22, or both. In another example, the target temperature is set to about-100 degrees Fahrenheit. In this case, the term "about" is known to the person skilled in the art. Alternatively, the term "about" may be understood to mean plus or minus 25 degrees Fahrenheit.

At block 116, the weld interface region 74 is inductively heated by the induction coil 22. The thermal gradient created by first cooling the first TPC12 maintains the temperature of the portion 76 closest to the induction coil 22 below the consolidation temperature while allowing the temperature of the weld interface region 74 to exceed the consolidation temperature.

In block 118, the first roller 28A and the second roller 28B apply consolidation pressure on the first TPC12 to merge the first TPC12 with the second TPC14 at the weld interface region 74 to produce a uniform fusion upon cooling. In another example, bellows 39 (fig. 1B) or other device may exert consolidation pressure on the second TPC 14. At block 120, the weld interface region 74 is induction welded along the weld line 26 by moving the induction coil 22 along the weld line 26 to weld the first TPC12 portion to the second TPC 14. Alternatively, the weld interface region 74 may be movable relative to the induction coil 22. It should be understood that

blocks

116, 118, and 120 may occur simultaneously. At block 122, feedback from the sensors 38 is used to adjust the induction welding process in real time. For example, the controller 30 may command different currents to the induction coil 22 to adjust the heat in real time, command the speed between the induction coil 22 and the weld interface region 74, and so forth.

Referring to fig. 14, with continued reference to fig. 1A and 12, there is shown a flow chart of a method 130 of inductively welding a first TPC12 to a second TPC14 using a system 10 having a cooling device 93, a second cooling device 100 and a second induction coil 102. The method 130 begins at block 132 by aligning the first TPC12 with the second TPC14 to form the weld interface region 74. In the example provided, the first TPC12 and the second TPC14 are all placed within a vacuum bag 70. A vacuum may then be applied to vacuum bag 70 by vacuum source 72. Alternatively, an inert gas may be pumped into the vacuum bag 70.

Next, at block 134, the first TPC12 is cooled using the cooling apparatus 93. In one example, a target temperature of the first TPC12 at the weld interface region 74 or portion 76 is set by the controller 30. Then, during cooling of the cooling apparatus 93, the controller 30 monitors the actual temperature of the first TPC12 at the weld interface region 74 or portion 76 using the sensor 38. The controller 30 then controls the amount of cooling provided by the cooling device 93 to match the actual temperature to the target temperature. The target temperature may be set using a look-up table, or may be calculated using specific factors given to achieve a specific thermal gradient. For example, setting the target temperature may determine the location of the weld interface region 74 relative to the induction coil 22 and set the target temperature based on the location of the weld interface region 74. Other factors may include the number of nozzles 96, the coolant flow rate from the nozzles 96, the distance from the cooling device 93 to the induction coil 22, the strength of the magnetic field generated by the induction coil 22, and the thickness of the first 12 and second 14 TPCs, as well as the carbon fiber induction coil 22 orientation and the velocity of the induction coil 22 relative to the weld interface region 74. In another example, the target temperature is set to about-100 degrees Fahrenheit. In this case, the term "about" is known to the person skilled in the art. Alternatively, the term "about" may be understood to mean plus or minus 25 degrees Fahrenheit.

At block 136, the weld interface region 74 is inductively heated by the induction coil 22. The thermal gradient created by first cooling the first TPC12 maintains the temperature of the portion 76 closest to the induction coil 22 below the consolidation temperature while allowing the temperature of the weld interface region 74 to exceed the consolidation temperature.

At block 138, the first roller 28A and the second roller 28B apply consolidation pressure on the first TPC12 to merge the first TPC12 with the second TPC14 at the weld interface region 74 to produce a uniform melt bond upon cooling. In another example, bellows 39 (fig. 1B) or other device may exert consolidation pressure on the second TPC 14. At block 140, the weld interface region 74 is induction welded along the weld line 26 by moving the induction coil 22 along the weld line 26 to weld the first TPC12 portion to the second TPC 14. Alternatively, the weld interface region 74 may be movable relative to the induction coil 22. It should be appreciated that blocks 136, 138, and 140 may occur simultaneously. At block 142, feedback from the sensors 38 is used to adjust the induction welding process in real time. For example, the controller 30 may command different currents to the induction coil 22 to adjust the amount of heating in real time, command the speed between the induction coil 22 and the weld interface region 74, and so forth. At block 144, the second cooling apparatus 100 and/or the second induction coil 102 is used to control the cooling rate of the weld interface region 74. The rate of cooling at the weld interface region 74 is controlled by controlling the amount of cooling and heating in real time by the controller 30 based on feedback received from the sensor 38 (fig. 1A).

Fig. 15 shows a cross-section of a stack of the first TPC12, the second TPC14 and the vacuum bag 70 on the tool base 16 using the heat spreader 20 in a side view of the induction coil 22 and the cooling apparatus 93. In this example, the cooling apparatus 93 cools the radiator 20 rather than directly cooling the first TPC 12. Cooling the heat sink 20 increases the thermal gradient and allows the heat sink 20 to remove more heat from the first TPC12 during induction than without cooling. In another example (not shown), a second heat sink 78 may be used in addition to the heat sink 20.

Fig. 16 shows a cross-section of the first TPC12, the second TPC14 and the vacuum bag 70 on the tool base 16 in a stack using the heat sink 20 in a side view of the cooling apparatus 93, the second cooling apparatus 100 and the second induction coil 102. In this example, the second cooling apparatus 100 cools the heat sink 20, rather than directly cooling the first TPC12 after induction welding through the induction coil 22. The second induction coil 102 operates as previously described because the heat sink 20 is not conductive. In another example (not shown), a second heat sink 78 may be used in addition to the heat sink 20.

Referring to fig. 17, with continued reference to fig. 1A and 15, a flow diagram of a method 150 of induction welding a first TPC12 to a second TPC14 using a system 10 having a cooling device 93 and a heat sink 20 is shown. The method 150 begins at block 152 by aligning the first TPC12 with the second TPC14 to form the weld interface region 74.

Next, at block 154, the heat sink 20 is placed on the first TPC 12. As noted above, the heat sink 20 preferably covers the weld interface region 74 at least along the weld line 26. Because the heat sink 20 is flexible, the heat sink 20 conforms to the surface profile of the first TPC12, whether planar or non-planar, as shown in fig. 2B. In the example provided, the first TPC12, the second TPC14 and the heat spreader 20 are all placed within a vacuum bag 70. A vacuum may then be applied to vacuum bag 70 by vacuum source 72. An inert gas may be pumped into the vacuum bag 70.

At block 156, the heat sink 20 is cooled using the cooling apparatus 93. In one example, a target temperature of the heat sink 20 is set by the controller 30. Then, during cooling of the cooling device 93, the controller 30 monitors the actual temperature control of the radiator 20 using the sensor 38. Then, the controller 30 controls the amount of cooling provided by the cooling device 93 so that the actual temperature matches the target temperature. The target temperature may be set using a look-up table, or may be calculated using specific factors given to achieve a specific thermal gradient. For example, setting the target temperature may determine the location of the weld interface region 74 relative to the induction coil 22 and set the target temperature based on the location of the weld interface region 74. Other factors may include the number of nozzles 96, the coolant flow rate from the nozzles 96, the distance from the cooling device 93 to the induction coil 22, the strength of the magnetic field generated by the induction coil 22, and the thickness and carbon fiber orientation of the first TPC12 and the second TPC 14. In another example, the target temperature is set to about-100 degrees Fahrenheit. In this case, the term "about" is known to the person skilled in the art. Alternatively, the term "about" may be understood to mean plus or minus 25 degrees Fahrenheit.

At block 158, the weld interface region 74 is inductively heated by the induction coil 22. The heat sink 20 cooled at block 156 maintains the temperature of the portion 76 closest to the induction coil 22 below the consolidation temperature while allowing the temperature of the weld interface region 74 to exceed the consolidation temperature.

At block 160, the first roller 28A and the second roller 28B apply consolidation pressure on the first TPC12 to merge the first TPC12 with the second TPC14 at the weld interface region 74 to produce a uniform melt bond upon cooling. In another example, bellows 39 (fig. 1B) or other device may exert consolidation pressure on the second TPC 14. At block 162, the weld interface region 74 is inductively welded along the weld line 26 by moving the induction coil 22 along the weld line 26 to partially weld the first TPC12 to the second TPC 14. Alternatively, the weld interface region 74 may be movable relative to the induction coil 22. It should be appreciated that blocks 158, 160, and 162 may occur simultaneously. At block 164, feedback from the sensors 38 is used to adjust the induction welding process in real time. For example, the controller 30 may command different currents to the induction coil 22 to adjust the heat in real time, command the speed between the induction coil 22 and the weld interface region 74, and so forth. Referring to fig. 18, with continued reference to fig. 1A and 16, there is shown a flow chart of a method 170 of inductively welding a first TPC12 to a second TPC14 using a system 10 having a heat sink 20, a cooling device 93, a second cooling device 100, and a second induction coil 102. The method 170 begins at block 172 by aligning the first TPC12 with the second TPC14 to form the weld interface region 74.

Next, at block 174, the heat sink 20 is placed on the first TPC 12. As noted above, the heat sink 20 preferably covers the weld interface region 74 at least along the weld line 26. Because the heat sink 20 is flexible, the heat sink 20 conforms to the surface profile of the first TPC12, whether planar or non-planar, as shown in fig. 2B. In the example provided, the first TPC12, the second TPC14 and the heat spreader 20 are all placed within a vacuum bag 70. A vacuum may then be applied to vacuum bag 70 by vacuum source 72. Alternatively, an inert gas may be pumped into the vacuum bag 70.

At block 176, the heat sink 20 is cooled using the cooling apparatus 93. In one example, a target temperature of the heat sink 20 is set by the controller 30. Then, during cooling of the cooling device 93, the controller 30 monitors the actual temperature of the radiator 20 using the sensor 38. Then, the controller 30 controls the amount of cooling provided by the cooling device 93 so that the actual temperature matches the target temperature. The target temperature may be set using a look-up table, or may be calculated using specific factors given to achieve a specific thermal gradient. For example, setting the target temperature may determine the location of the weld interface region 74 relative to the induction coil 22 and set the target temperature based on the location of the weld interface region 74. Other factors may include the number of nozzles 96, the coolant flow rate from the nozzles 96, the distance from the cooling device 93 to the induction coil 22, the strength of the magnetic field generated by the induction coil 22, as well as the thickness of the first and

second TPCs

12, 14, the carbon fiber orientation, and the speed of movement of the induction coil 22 relative to the weld interface region 74. In another example, the target temperature is set to about-100 degrees Fahrenheit. In this case, the term "about" is known to the person skilled in the art. Alternatively, the term "about" may be understood to mean plus or minus 25 degrees Fahrenheit.

At 178, the weld interface region 74 is inductively heated by the induction coil 22. The heat sink 20 cooled at block 176 maintains the temperature of the portion 76 closest to the induction coil 22 below the consolidation temperature while allowing the temperature of the weld interface region 74 to exceed the consolidation temperature.

At block 179, the first roller 28A and the second roller 28B apply consolidation pressure on the first TPC12 to merge the first TPC12 with the second TPC14 at the weld interface region 74 to produce a uniform melt bond upon cooling. In another example, bellows 39 (fig. 1B) or other device may exert consolidation pressure on the second TPC 14. At block 180, the weld interface region 74 is induction welded along the weld line 26 by moving the induction coil 22 along the weld line 26 to weld the first TPC12 portion to the second TPC 14. Alternatively, the weld interface region 74 may be movable relative to the induction coil 22. It should be appreciated that blocks 178, 179, and 180 may occur simultaneously. At block 182, feedback from the sensor 38 is used to adjust the induction welding process in real time. For example, the controller 30 may command different currents to the induction coil 22 to adjust the amount of heating in real time, command the speed between the induction coil 22 and the weld interface region 74, and so forth. At block 184, the second cooling apparatus 100 and/or the second induction coil 102 is used to control the cooling rate of the weld interface region 74. The cooling rate at the weld interface region 74 is controlled by controlling the amount of cooling and heating in real time by the controller 30 based on feedback received from the sensor 38 (fig. 1A).

Fig. 19 shows an alternative example of a heat sink 185 according to the principles of the present disclosure. The heat sink 185 is configured to absorb and dissipate heat from the first TPC12 and/or the second TPC 14. The heat sink 185 includes a plurality of tiles 186 flexibly connected by joints 187. The knuckles 187 are disposed between the tiles 186. The tiles 186 are substantially similar to the tiles 40 and the knuckles 187 are substantially similar to the knuckles 42 of the heat sink 20 shown in fig. 2A. However, the heat sink 185 also includes a plurality of fluid passages 188 formed therethrough. A fluid passage 188 extends through each tile 186 and through each knuckle 187. Sets of fluid passages 188 between adjacent tiles 186 and knuckles 187 are connected together in series to form a plurality of fluid paths 188A through the heat sink 185. Fluid paths 188A are preferably unidirectional and parallel to each other. However, fluid path 188A may have other configurations, such as non-parallel or offset. In the example provided, each tile 186 includes three fluid channels 188, however, it should be understood that any number of fluid channels 188 may be employed. Fluid passage 188 is sized to flow a coolant fluid therethrough, as described below. In one example, the fluid passage 188 has a diameter of about 0.042 inches. In another example, the fluid channel 188 has a diameter of about 0.082 inches. In one aspect, manifold 189 is connected to radiator 185. The manifold 189 includes a port 190, the port 190 communicating with the fluid passage 188 via a plurality of internal passages (not shown) to provide a single connection port for the heat sink 185.

Fig. 20 shows a flow diagram of a method 200 for creating a heat sink 185 using the heat sink manufacturing system 50 of fig. 3. The method 200 begins at block 202 where a fluid channel 188 is formed through each tile 186 at block 202. In one example, the fluid channels 188 are drilled in the tiles 186 using ultrasonic machining (not shown).

At block 204, as shown in fig. 21, a plurality of rods 205 are inserted into the fluid channel 188. The lever 193 may be coated with a release material to assist in later removal of the lever 193. The rod 193 is sized to match the diameter of the fluid passage 188. Each rod 193 passes through a plurality of tiles 186 having aligned fluid passages 188. At block 206, tiles 186 are arranged in a pattern. For example, the tiles 186 are placed on the backing material 54 between the clips 58. The backing material 54 holds the tiles 186 in place while the clips 58 space the tiles 186 apart. Thus, the pattern is defined by the jig 58. The tiles 186 may be primed with a primer prior to placement on the backing material 54. Preferably, the tiles 186 are arranged such that the fluid channels 188 are aligned with one another. It should be understood that

blocks

204 and 206 may be performed in any order without departing from the scope of the present disclosure.

At block 208, the frame 56 and the clamp 58 are removed, leaving the gap 44 between the tiles 186. Next, at block 210, tiles 40 are flexibly joined together with flexible adhesive 45. A flexible adhesive 45 is applied within the gap 44. The stem 205 prevents the flexible adhesive 45 from entering the fluid channel 188 formed in the tile 186. In addition, the flexible adhesive 45 flows around the stem 205 to form the fluid channel 188 through the knuckle 187. The flexible adhesive 45 is then preferably cured for a period of time. Once cured, the rod 193 is removed from the fluid channel 188 at block 212. The assembled heat spreader 185 may be removed from the backing material 54.

Fig. 22 shows an enlarged partial cross-section of the system 10 showing a stack of the first TPC12, the second TPC14 and the heat sink 185 on the tool base 16. The first TPC12 is disposed on top of the second TPC 14. A heat sink 185 is disposed on top of the first TPC12 between the induction coil 22 and the first TPC 12. The first roller 28A and the second roller 28B apply consolidation pressure on the first TPC12 through the heat spreader 185 to compress the first TPC12 onto the second TPC 14. Fluid path 188A of radiator 185 is connected to pump 220 which supplies coolant to radiator 185. The pump 220 is configured to pump a coolant, such as water or a high temperature transfer fluid, through the fluid path 188A of the radiator 185. An example of a high temperature transfer fluid is Dynalene SF from Dynalene inc. In one example, the pump 220 is connected to a port 190 (fig. 19) of the manifold 189.

During induction welding, the controller 30 (fig. 1A) commands a current through the induction coil 22 to generate the magnetic field 25. The magnetic field 25 heats the carbon fibers within the first TPC12 and the second TPC 14. The portion 76 of the first TPC12 that is closer to the induction coil 22 is heated to a greater extent than at the weld interface region 74. The coolant is pumped through the radiator 185 by the pump 220. Heat generated in the first TPC12 is absorbed by the heat sink 185 and dissipated into the coolant in the fluid path 188A. The coolant is pumped out of the radiator 185 to dissipate heat in the first TPC 12.

When the thermoplastic in the weld interface region 74 is heated above the melting point or consolidation temperature of the material, the first roller 28A and the second roller 28B exert consolidation pressure on the first TPC12 to cause the first TPC12 to merge with the second TPC14 at the weld interface region 74, thus creating a uniform melt bond upon cooling. In one example, the weld interface region 74 is heated to about 20 degrees above the consolidation temperature.

Once heated, the coolant may be pumped back through the heat sink 185 to control the cooling rate of the weld interface region 74. In one example, coolant is circulated back through the heat sink 185 at a temperature of about 400 degrees fahrenheit after induction welding to control the cooling rate of the weld interface region 74. The input temperature and flow rate of the coolant through the heat sink 185, as well as the power supplied to the induction coil 22, can be adjusted to control the cooling rate of the weld interface region 74.

The controller 30 then commands the robot arm 24 to move along the weld line 26 (fig. 1A) in the first direction 26A (fig. 1A) to partially weld the first TPC12 to the second TPC 14. Instead, the weld interface region 74 moves relative to the induction coil 22. Feedback from the sensor 38 (fig. 1A) can be used to command different currents to the induction coil 22 to regulate heat in real time.

Fig. 23 illustrates another example of a heat sink 250 according to the principles of the present disclosure. The heat sink 250 is similar to the heat sink 185 shown in fig. 19. However, a fluid passage 188 is provided within the knuckle 187. Thus, fluid passages 188 are disposed between tiles 186 rather than through tiles 186. No holes are drilled from the tiles 186 and therefore can withstand greater compressive forces than in the heat sink 185. The fluid passage 188 is able to withstand consolidation pressures during induction welding without pinching and cutting off the fluid passage 188.

Fig. 24 illustrates another example of a heat sink 300 according to the principles of the present disclosure. The heat sink 250 is similar to the heat sink 185 shown in FIG. 19, however, the fluid passage 188 is oval-shaped. In addition, only one fluid passage 188 is formed in each tile 186. The elliptical shape of fluid passage 188 relative to heat sink 185 reduces the pressure drop and reduces any chance of restriction within fluid passage 188. Additionally, the oval shaped fluid passage 188 has increased heat transfer relative to the heat sink 185 due to the greater surface area of the fluid passage 188. It is understood that other shapes, including square or star shapes, may be employed without departing from the scope of this disclosure.

Fig. 25 illustrates a top view of a portion of another example of a heat sink 400 according to the principles of the present disclosure. Heat spreader 400 includes a plurality of tiles 402 connected by backing 404. The tiles 402 are made of a material that is electrically and thermally conductive, and like the tiles 40 of the heat sink 20 (fig. 2A), the tiles 402 are hexagonal rather than square. However, it should be understood that tile 402 may have any number of sides and shapes without departing from the scope of the present disclosure. Tile 402 is held in place by backing 404.

Backing 404 flexibly holds tiles 402 together and provides flexibility to heat spreader 400, allowing heat spreader 400 to conform to a curved surface (not shown). Tiles 402 are arranged in a single layer in a parquet or geometric pattern. Each tile 402 defines an air gap 406 therebetween. The air gap 406 is devoid of material. In one example, the width 407 of the air gap 406 is between about 0.005 inches and about 0.1 inches, preferably about 0.040 inches. In this case, the term "about" is known to the person skilled in the art. Alternatively, the term "about" can be understood to mean plus or minus 0.005 inches. The air gap 406 allows for increased cooling of the tiles 402 using air flow, as will be described below. Backing 404 is preferably a web of interlaced fibers 408, only some of which are shown in fig. 25. The fibers 408 are non-conductive and do not melt during induction welding. The fibers 408 may be composed of glass or oxide ceramic, and may be embedded in silicone or other materials. In another example, the backing 404 is composed of a fiberglass cloth or mesh impregnated with Polytetrafluoroethylene (PTFE).

In one example, the heat sink 400 includes a tube 410 disposed along a longitudinal edge 412 of the heat sink 400. In one example, the tube 410 is bonded to the backing 404. In another example, the tube 410 is constructed of PTFE. Additionally, or alternatively, the tube 410 may not be disposed in a portion of the heat sink 400 along the longitudinal edges 412 (e.g., lateral edges, etc.). The tube 410 is connected to a source of pressurized gas 414. The pressurized gas source 414 may include a fan, a pump, or a pressurized tank. The pressurized gas source 414 delivers a gas, such as air or cold CO, through the tube 410₂. The tube 410 includes an aperture 416 disposed therethrough. The holes 416 are aligned with the air gaps 406 between the tiles 402. During induction welding, gas is provided by a pressurized gas source 414 and is communicated through the tube 410 and the aperture 416. The gas then passes through the air gap 406 and absorbs and dissipates heat from the tiles 402.

Fig. 26 shows a partial cross-section of a heat sink 400. Tile 402 is adhered to backing 404 by adhesive 420. The adhesive 420 need not be flexible because the backing 404 is flexible. Examples of suitable binders include silicone, PTFE, Polybenzimidazole (PBI), High Performance Polyamides (HPPA), Polyamides (PI), Polyamides (PAI), polyketones, polysulfone derivatives-a, fluoropolymers, Polyetherimides (PEI), polybutylene terephthalate (PBT), polyphenylene sulfide, syndiotactic polystyrene and polycyclohexanedimethyl terephthalate (PCT). Another example of a suitable adhesive is an epoxy resin, heat cured two-component system with a liquid resin and a powder hardener. For example, the binder may be one registered to elastas PDG, inc

5403 or

5302. In another example, the adhesive 420 may beA silicone pressure sensitive adhesive. In another example, the adhesive 420 is composed of the same type of silicone used in the knuckles 42 (fig. 2A) of the heat sink 20. Fig. 27 shows a cross-section of another variation of a heat spreader 450 in which tiles 402 are embedded within an adhesive 420. In this example, air gap 406 is filled with adhesive 420.

Fig. 28 and 29 show a partial cross section of a system 500 for induction welding a first TPC12 to a second TPC14 using a heat sink 400. The system 500 operates in a similar manner as the system 10 (FIG. 1A) described above. In the example provided, the first TPC12 and the second TPC14 are curved, so the first TPC12 defines a curved contact surface 502. The first TPC12 and the second TPC14 are supported by a curved tool base 504. The bellows 506 is induction welded through the curved tool base 504. Alternatively, pneumatic cylinders or mechanical actuators, such as springs, belts or levers, may be used to apply the consolidation pressure.

A heat sink 400 is disposed on the first TPC12 between the induction coil 22 and the second TPC 14. Backing 404 flexes to allow tile 402 to contact flexed contact surface 502. The contact between tiles 402 and curved contact surface 502 maximizes heat transfer. In another example (not shown), the backing 404 is impregnated with PTFE and the backing 404 is in contact with the curved contact surface 502. The PTFE causes the backing 404 to act as a release film and prevents the heat spreader 400 from adhering to the first TPC12 during induction welding.

The heat sink 400 is held in place by a heat sink holder 508. Alternatively, or in addition, a vacuum bag 70 (fig. 1A) may be used to hold the heat spreader 400 in contact with the curved contact surface 502. For example, as shown in fig. 28, an air gap 510 is formed opposite the weld interface region 74 only when the backing 404 is bent. In this example, air flow is not used to help cool the tiles 402, and the heat sink may only accommodate curved surfaces in two dimensions (i.e., x and y coordinates). In another example, shown in fig. 29, when the backing 404 is bent, an air gap 512 is also formed near the bent contact surface 502. In this example, air flow is used through

air gaps

510, 512 to help cool tile 402. In addition, the heat sink 400 can accommodate curved surfaces in three dimensions (i.e., x, y, and z coordinates). Induction welding is performed in a similar manner as described above with reference to fig. 1A.

The above-described

systems

10 and 500,

heat spreaders

20, 185, 250, 300, and 400, and

methods

60, 80, 110, 130, 150, and 170 each operate to control the induction heating of the first TPC12 and the second TPC14 to concentrate heat along the weld interface region 74. Thus, temperatures in the portion 76 of the first TPC12 closest to the induction coil 22 and the portion 88 of the second TPC14 exceeding the consolidation temperature are avoided.

Aspects of

systems

10 and 500 and

methods

60, 80, 110, 130, 150, and 170 may be employed in the context of aircraft manufacturing and service method 1000 as shown in fig. 30 and aircraft 1002 as shown in fig. 31. During pre-production, exemplary method 1000 may include specification and design 1004 of aircraft 1002 and material procurement 1006. During production, component and subassembly manufacturing 1008 and system integration 1010 of aircraft 1002 occurs. Thereafter, the aircraft 1002 may be certified and delivered 1012 to be placed into service 1014. During customer use, aircraft 1002 is scheduled for routine maintenance and service 1016 (which may also include modification, reconfiguration, refurbishment, and so on). The apparatus and methods embodied herein may be employed in any suitable stage or stages of production and service described in method 1000 (e.g., specification and design 1004, material procurement 1006, component and subassembly manufacturing 1008, system integration 1010, certification and delivery 1012, service 1014, maintenance and service 1016) and/or any suitable component of aircraft 1002 (e.g., fuselage 1018, system 1020, interior 1022, propulsion system 1024, electrical system 1026, hydraulic system 1028, environmental system 1030).

Each of the processes of the systems and methods described herein may be performed or carried out by a system integrator, a third party, and/or an operator (e.g., a customer). For purposes of description, a system integrator may include, but is not limited to, any number of aircraft manufacturers and major system subcontractors; the third party may include, but is not limited to, any number of vendors, subcontractors, and suppliers; the operator may be an airline, leasing company, military entity, service organization, and so on.

As shown in fig. 31, aircraft 1002 produced by exemplary method 1000 may include an airframe 1018 with a plurality of systems 1020 and an interior 1022. Examples of systems 1020 include one or more of a propulsion system 1024, an electrical system 1026, a hydraulic system 1028, and an environmental system 1030. Any number of other systems may be included. Although an aerospace example is shown, the principles of the disclosure may be applied to other industries, such as the automotive industry.

The systems and methods described above may be employed in any one or more stages of exemplary method 1000. For example, components or subassemblies corresponding to component and subassembly manufacturing 1008 may be fabricated or manufactured in a similar manner as components or subassemblies produced while the aircraft 1002 is in use. Also, for example, one or more device aspects, method aspects, or a combination thereof may be utilized in assembly and subassembly manufacturing 1008 and system integration 1010 by substantially speeding up assembly of aircraft 1002 or reducing the cost of aircraft 1002. Similarly, in use of aircraft 1002, for example and without limitation, maintenance and services 1016, one or more of equipment aspects, method aspects, or a combination thereof may be utilized. For example, the techniques and systems described herein may be used for material procurement 1006, component and subassembly manufacturing 208, system integration 1010, service 1014, and/or maintenance and service 1016, and/or may be used for airframe 1018 and/or interior 1022. These techniques and systems may even be used for systems 1020 including, for example, propulsion systems 1024, electrical systems 1026, hydraulic systems 1028, and/or environmental systems 1030.

The description of the disclosure is merely exemplary in nature and variations that do not depart from the gist of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.

Claims

1. A heat sink (20) for induction welding, the heat sink (20) comprising:

a joint (42) flexibly connecting the tiles (40) together.

2. The heat sink (20) according to claim 1, wherein the tiles (40) are comprised of aluminum nitride.

3. The heat sink (20) according to claim 1, wherein the tiles (40) are comprised of beryllium oxide.

4. The heat sink (20) according to claim 1, wherein the tiles (40) are arranged in a single layer.

5. The heat sink (20) according to claim 1, wherein the tiles (40) define gaps (44) between the tiles (40) and the joints (42) are disposed within the gaps (44).

6. The heat sink (20) of claim 1, wherein the knuckle (42) is constructed of silicone having a long-term degradation temperature in vacuum or air of greater than about 400 degrees fahrenheit.

7. The heat sink (20) according to claim 6, wherein the silicone has an elongation between 12% and 670%.

8. The heat sink (20) of claim 1, wherein the tiles (40) have a thermal conductivity greater than about 75W/mK.

9. The heat sink (20) according to claim 1, wherein the tiles (40) have a heat capacity of greater than about 500J/K/kg.

10. A method (60) of forming a heat sink (20), the method comprising:

flexibly connecting the tiles (40).

11. The method of claim 10 wherein flexibly engaging the tiles (40) comprises flexibly engaging the tiles (40) with mechanical hinges (47) disposed within the gaps (44).

12. The method of claim 10 wherein flexibly engaging the tiles (40) comprises flexibly engaging the tiles (40) with a flexible adhesive (45) disposed within the gap (44).

13. The method of claim 12 wherein flexibly engaging the tiles (40) with the flexible adhesive (45) comprises injecting the flexible adhesive (45) into the gap (44).

14. The method of claim 9, further comprising curing the flexible adhesive (45).

15. The method of claim 10 wherein spacing the tiles (40) comprises spacing the tiles (40) on a backing material (54).