Thermoplastic welding apparatus and method

• US 9,586,362 B2
• Filed: 05/17/2011
• Issued: 03/07/2017
• Est. Priority Date: 05/17/2011
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Matsen, Marc R., Negley, Mark A., Geren, William Preston, Miller, Robert James
• Primary Examiner(s): Orlando, Michael N
• Assistant Examiner(s): Bradford, Elizabeth
• Application Number:
  US13/109,061
• Publication Number:
  US 20120291948A1
• Time in Patent Office: 2,121 Days
• Field of Search: 156/272.2, 156/272.4, 156/285, 156/379.6, 156/379.7, 156/381, 219/633, 264/403
• US Class Current: 1/1
• CPC Class Codes: B29C 65/3612 comprising fillers
• CPC Class Codes: B29C 65/3644 being a ribbon, band or strip
• CPC Class Codes: B29C 65/3668 characterised by the means for supplying heat to said heated elements which remain in the join, e.g. special induction coils
• CPC Class Codes: B29C 65/3676 being metallic
• CPC Class Codes: B29C 66/00145 Vacuum, e.g. partial vacuum
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/41 Joining substantially flat articles B29C66/47 and subgroups take precedence; Making flat seams in tubular or hollow articles B29C66/51 and subgroups take precedence
• CPC Class Codes: B29C 66/474 said single elements being substantially non-flat
• CPC Class Codes: B29C 66/524 Joining profiled elements
• CPC Class Codes: B29C 66/721 Fibre-reinforced materials B29C66/729 takes precedence
• CPC Class Codes: B29C 66/7212 characterised by the composition of the fibres
• CPC Class Codes: B29C 66/7392 characterised by the material of at least one of the parts being a thermoplastic
• CPC Class Codes: B29C 66/73921 characterised by the materials of both parts being thermoplastics
• CPC Class Codes: B29C 66/7394 characterised by the material of at least one of the parts being a thermoset
• CPC Class Codes: B29C 66/8122 characterised by the composition of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps
• CPC Class Codes: B29C 66/8126 characterised by the intensive physical properties or by the optical properties of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps
• CPC Class Codes: B29C 66/81457 comprising a block or layer of deformable material, e.g. sponge, foam, rubber pressing elements supported or backed-up by resilient material B29C66/8161
• CPC Class Codes: B29K 2307/04 Carbon
• CPC Class Codes: B29K 2309/08 Glass
• CPC Class Codes: B29K 2905/12 Iron
• CPC Class Codes: B29K 2909/02 : Ceramics
• CPC Class Codes: B29K 2995/0008 : Magnetic or paramagnetic
• CPC Class Codes: B29L 2031/3076 : Aircrafts blades, propellers B29L2031/08
• CPC Class Codes: H05B 2206/023 : using the curie point of the material in which heating current is being generated to control the heating temperature
• CPC Class Codes: H05B 6/105 : using a susceptor

Abstract

A thermoplastic welding apparatus includes a thermoplastic welding tool, at least one tooling surface in the thermoplastic welding tool, a magnetic induction coil in the thermoplastic welding tool and generally encircling the at least one tooling surface and at least one smart susceptor in the thermoplastic welding tool at the at least one tooling surface. The magnetic induction coil is adapted to generate a magnetic flux field oriented generally parallel to a plane of the at least one smart susceptor.

Claims

1. A thermoplastic welding apparatus comprising:

a first composite part and a second composite part;

a thermoplastic welding tool having a tooling surface defining at least a portion of a cavity of the welding tool, the cavity to receive the first and second composite parts;

a smart susceptor positioned in the cavity of the welding tool between opposing surfaces of the first composite part and the second composite part;

a tape attached only to a perimeter of the first and second composite parts and in contact with only a portion of the tooling surface defined by the perimeter of the first and second composite parts when the first and second composite parts are positioned in the cavity of the welding tool, the tape to provide a sealed portion in communication with the tooling surface and a non-sealed portion in communication with the cavity;

a vacuum apparatus to apply a vacuum to the sealed portion such that a welding joint between the sealed portion and the non-sealed portion is exposed to a pressure differential provided by the vacuum in the sealed portion and a pressure provided in the non-sealed portion, the pressure differential to compress the smart susceptor between the first and second composite part while the vacuum is applied to the welding joint during welding; and

a magnetic induction coil to extend through the welding tool and positioned adjacent the cavity, the magnetic induction coil to generate a magnetic flux field oriented generally parallel to a plane of the smart susceptor.

2. The apparatus of claim 1, wherein the smart susceptor comprises molypermalloy.

3. The apparatus of claim 1, further comprising a ferromagnetic material embedded in the tooling surface and positioned adjacent the cavity to direct the magnetic flux field to the smart susceptor and reduce leakage of the magnetic flux field into one of the parts.

4. The apparatus of claim 1, further comprising a non-electrically conductive material positioned adjacent the tooling surface.

5. The apparatus of claim 4, wherein the non-electrically conductive material comprises an elastomeric material.

6. The apparatus of claim 4, further comprising a ferromagnetic material embedded in the tooling surface adjacent the non-electrically conductive material.

7. The apparatus of claim 6, wherein the ferromagnetic material is embedded in the tooling surface on respective sides of the non-electrically conductive material and the smart susceptor.

8. The apparatus of claim 6, wherein the ferromagnetic material comprises ferrite powder.

9. A thermoplastic welding apparatus comprising:

a first composite part and a second composite part;

a thermoplastic welding tool having a tooling space to receive the first and second composite parts, wherein the tooling space defines a tooling surface to receive the first composite part;

at least one smart susceptor positioned between the first composite part and the second composite part;

a seal directly attached to only perimeter edges of the first composite part and the second composite part to form a gas seal over a welding joint defined by a portion of the first composite part, a portion of the second composite part and the smart susceptor, wherein tooling surface, the seal, and the portions of the first and second composite parts and the smart susceptor define a joint volume;

a vacuum generator to provide a vacuum to the portions of the first and second composite parts positioned within the joint volume at the welding joint when the first and second composite parts are welded together and to enable a gas pressure within the tooling space to be applied to portions of the first composite part or the second composite part positioned outside of the joint volume such that a pressure differential provided by the vacuum and the gas pressure applies a welding pressure to compress the smart susceptor between the first and second composite parts; and

a magnetic induction coil positioned in the thermoplastic welding tool adjacent the at least one tooling surface, the magnetic induction coil to generate a magnetic flux field oriented generally parallel to a plane of the at least one susceptor.

10. The apparatus of claim 9, wherein the smart susceptor comprises molypermalloy.

11. The apparatus of claim 9, further comprising a ferromagnetic material embedded in the tooling surface adjacent the smart susceptor.

12. The apparatus of claim 9, further comprising a non-electrically conductive material positioned in the tooling surface.

13. The apparatus of claim 12, wherein the non-electrically conductive material comprises an elastomeric material.

14. The apparatus of claim 12, further comprising a ferromagnetic material embedded in the tooling surface adjacent the non-electrically conductive material.

15. The apparatus of claim 14, wherein the ferromagnetic material is embedded in the tooling surface on respective sides of the non-electrically conductive material.

16. The apparatus of claim 14, wherein the ferromagnetic material comprises ferrite powder.

17. The apparatus of claim 9, wherein the seal comprises an L-shaped cross-section.

18. The apparatus of claim 17, wherein the seal comprises a first leg attached to a first side surface of the first composite part and a first side surface of the second composite part, and a second leg attached only to a portion of a second surface of the second composite part, the second surface of the second composite part being non-parallel relative to the first surface of the first composite part.

19. A thermoplastic welding apparatus comprising:

a first composite part;

a second composite part;

a smart susceptor positioned between the first and second composite parts;

a tool having a tooling surface to define a cavity to receive the first composite part, the second composite part and the smart susceptor positioned between the first and second composite parts;

a tape attached to a perimeter of the first composite part and in contact with only a portion of the tooling surface about perimeter edges of the first composite part and the second composite part, the tape to form a gas seal within a perimeter defined by the tape and defined by the smar susceptor and the first and second composite parts positioned within the cavity;

a vacuum generator to apply a vacuum to the tooling surface, the tape creating a seal between at least a portion of the tooling surface positioned inside the perimeter edges defined by the tape and the cavity, the seal to enable a welding pressure provided by a pressure differential between an internal gas pressure in the cavity and the vacuum provided to the tooling surface inside the perimeter of the tape during a welding process to cause the smart susceptor to compress between the first composite part and the second composite part; and

a first magnetic induction coil provided in the tool, the first magnetic induction coil to generate a first magnetic flux field adjacent the smart susceptor when the smart susceptor is positioned within the thermoplastic welding apparatus.

20. The apparatus of claim 19, further comprising a second magnetic inductor provided in the second tool adjacent the tooling surface, the second magnetic inductor to generate a second magnetic flux field adjacent the smart susceptor.

21. The apparatus of claim 19, further comprising a ferromagnetic material embedded in the tooling surface, the ferromagnetic material to direct the magnetic flux field toward the smart susceptor and away from the first and second composite parts.

22. The apparatus of claim 19, further comprising a non-electrically conductive material to be positioned adjacent the tooling surface.

23. The apparatus of claim 22, wherein the vacuum enables the parts and the smart susceptor to be held in contact when the parts are being welded together.

24. The apparatus of claim 23, wherein the vacuum is provided within a joint volume inside a perimeter defined by the seal.

25. The apparatus of claim 24, wherein a tooling force is applied to the parts to supply a welding pressure when the vacuum is provided within the joint volume.