Induction molding for parts having thermoplastic portions

Patent metadata

Field	Value
Publication number	US-10792842-B2
Application number	US-201715791683-A
Country	US
Kind code	B2
Filing date	Oct 24, 2017
Priority date	Oct 24, 2017
Publication date	Oct 6, 2020
Grant date	Oct 6, 2020

Abstract

Systems and methods are provided for molding systems that have a low thermal mass. One embodiment is a first tool that includes a first frame. The first frame includes a first set of plates of magnetically permeable material, and a material disposed between plates of the first set. The first tool also includes a first set of induction coils that are disposed within the first frame and that generate a first electromagnetic field, and a first susceptor that extends from the first set of plates. The first susceptor generates heat in response to the first electromagnetic field. The first tool further includes a mold that extends from the first susceptor and receives heat via conductive heat transfer from the first susceptor. Each plate of the first set is thinner than a skin depth at which the first electromagnetic field would generate an electrical induction current.

First claim

What is claimed is:

1. An apparatus comprising:
a first tool comprising:
a first frame comprising:
a first set of plates of magnetically permeable material that are parallel with each other and face each other; and
a material, disposed between plates of the first set, that prevents electrical conduction between the plates;

a first set of induction coils that are disposed within slots in the first frame and that generate a first electromagnetic field;
a mold that forms a lower surface of the first tool; and
a first susceptor interposed between the mold and the first frame, wherein the first susceptor is made of a ferromagnetic material that generates heat in response to the first electromagnetic field, and that has a Curie point within ten degrees Celsius of a processing temperature for a thermoplastic portion of a part;
wherein the mold includes a plurality of tooling plugs that project from the lower surface of the first tool, and contact the first susceptor to receive heat via conductive heat transfer from the first susceptor,
wherein each plate of the first set is thinner than a skin depth at which the first electromagnetic field would generate an electrical induction current in the plates of the first set;
wherein a thickness of walls of the tooling plugs is less than a skin depth at which the first electromagnetic field would generate an electrical induction current in the tooling plugs.

2. The apparatus of claim 1 further comprising:
a second tool comprising:
a second frame comprising:
a second set of plates of magnetically permeable material that are parallel with each other and face each other; and
a material, disposed between plates of the second set, that prevent electrical conduction between the plates;

a second set of induction coils that are disposed within slots in the second frame and that generate a second electromagnetic field; and
a second susceptor of ferromagnetic material that generates heat in response to the second electromagnetic field, wherein the second susceptor is recessed within the second frame and defines a receptacle that is dimensioned to receive the mold,
wherein each plate of the second set is thinner than a skin depth at which the second electromagnetic field would generate an electrical induction current in the plates of the second set.

3. The apparatus of claim 2 wherein:
the first susceptor and the second susceptor each comprise an alloy of iron, nickel, and cobalt.

4. The apparatus of claim 1 further comprising:
additional susceptors that are inserted into the mold, and that are made from a ferromagnetic material that generates heat in response to the first electromagnetic field.

5. The apparatus of claim 4 wherein:
the walls of each of the tooling plugs include inner walls that do not contact the part, and outer walls that contact the part, and
at least one of the additional susceptors is inserted in an outer cavity between the inner walls and the outer walls.

6. The apparatus of claim 1 wherein:
the magnetically permeable material forming the first set of plates is non-magnetic stainless steel.

7. The apparatus of claim 1 wherein:
the mold is made from a ferromagnetic material that is chemically distinct from the ferromagnetic material of the first susceptor.

8. The apparatus of claim 1 wherein the first tool further comprises:
a base attached to the first frame; and
a plurality of supports interposed between the base and a corresponding one of the tooling plugs.

9. The apparatus of claim 8 wherein:
the supports are made from a magnetically permeable material.

10. The apparatus of claim 9 wherein:
the supports are made from non-magnetic stainless steel.

11. The apparatus of claim 9 wherein:
the supports are thinner than a skin depth at which the first electromagnetic field would generate an electrical induction current within the supports.

12. The apparatus of claim 9 wherein:
each of the supports comprises a hollow cylinder that includes a slit extending along a length of the hollow cylinder.

13. The apparatus of claim 1 wherein
the walls of the tooling plugs include inner walls that define an inner cavity for each of the tooling plugs.

14. The apparatus of claim 13 further comprising:
a cooling system in fluid communication with the inner cavity of each of the tooling plugs, and that applies a fluid to the inner cavity to cool the tooling plugs below a processing temperature.

15. The apparatus of claim 14 wherein:
the cooling system comprises a tube inserted into the inner cavity of each of the tooling plugs.

16. The apparatus of claim 15 wherein:
the tube comprises a port that enables fluid to travel from the tube to the inner cavity.

17. The apparatus of claim 1 wherein:
the magnetically permeable material forming the mold is non-magnetic stainless steel.

18. A molding system, comprising:
a first tool and a second tool that unite to shape a part;
the first tool comprises:
a first base;
a first frame attached to the first base;
a first set of induction coils disposed through the first frame that generate a first electromagnetic field;
a first susceptor disposed along a side of the first frame opposite the first base; and
a plurality of tooling plugs that contact the first susceptor, and that project from the first susceptor to form a surface of the first tool that faces the second tool to shape the part;

wherein a thickness of walls of the tooling plugs is less than a skin depth at which the first electromagnetic field would generate an electrical induction current in the tooling plugs.

19. The molding system of claim 18 wherein:
the second tool comprises:
a second base;
a second frame attached to the second base;
a second set of induction coils disposed through the second frame that generate a second electromagnetic field; and
a second susceptor disposed along a side of the second frame opposite the second base;

wherein the second susceptor defines a receptacle that faces the tooling plugs of the first tool.

20. The molding system of claim 18 wherein:
the walls of the tooling plugs include inner walls that define an inner cavity for each of the tooling plugs.

21. The molding system of claim 20 further comprising:
a cooling system that applies a cooling fluid to the inner cavity of each of the tooling plugs.

22. The molding system of claim 21 wherein:
the cooling system includes a tube in fluid communication with the inner cavity of each of the tooling plugs; and
the tube includes a hollow passage through which the cooling fluid travels, and ports disposed within the inner cavity where the cooling fluid exits the hollow passage into the inner cavity.

23. The molding system of claim 20 wherein:
the walls of the tooling plugs further include outer walls; and
an outer cavity is interposed between the inner walls and the outer walls.

24. The molding system of claim 23 wherein the first tool further comprises:
an additional susceptor disposed in the outer cavity.

25. The molding system of claim 18 wherein the first tool further comprises:
a plurality of supports disposed between the first base and the first susceptor;
wherein one of the supports is fastened to a corresponding one of the tooling plugs.

26. The molding system of claim 25 wherein each of the supports comprises:
a hollow cylinder having a slit extendin

Assignees

• Boeing Co

Inventors

• Matsen Marc R
• Dykstra William C
• Firth Lee Charles
• Henson Landon K
• Olaniyan Tunde A
• Hull John R

Classifications

• B29C70/46

  using matched moulds, e.g. for deforming sheet moulding compounds [SMC] or prepregs · CPC title

• Y02P70/10

  Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working · CPC title

• H05B6/105

  using a susceptor · CPC title

• H05B2206/023

  using the curie point of the material in which heating current is being generated to control the heating temperature · CPC title

• B29C33/06 Primary

  using radiation {, e.g. electro-magnetic waves, induction heating} · CPC title