Induction heating cells with cauls over mandrels methods of using thereof

Patent metadata

Field	Value
Publication number	US-10994450-B2
Application number	US-202016843596-A
Country	US
Kind code	B2
Filing date	Apr 8, 2020
Priority date	Dec 14, 2017
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

Disclosed herein are induction heating cells and methods of using these cells for processing. An induction heating cell may be used for processing (e.g., consolidating and/or curing a composite layup having a non-planar portion. The induction heating cell comprises a caul, configured to position over and conform to this non-planar portion. Furthermore, the cell comprises a mandrel, configured to position over the caul and force the caul again the surface of the feature. The CTE of the caul may be closer to the CTE of the composite layup than to the CTE of the mandrel. As such, the caul isolates the composite layup from the dimensional changes of the mandrel, driven by temperature fluctuations. At the same time, the caul may conform to the surface of the mandrel, which can be used to define the shape and transfer pressure to the non-planar portion.

First claim

What is claimed is:

1. A method comprising:
a step of positioning a composite layup over a die, wherein the composite layup comprises a non-planar portion, extending away from the die, and
a step of positioning a caul over the composite layup;
a step of positioning a mandrel over the caul, wherein a difference between a coefficient of thermal expansion (CTE) of the caul and a CTE of the composite layup is less than a difference between the CTE of the mandrel and the CTE of the caul;
a step of heating the composite layup; and
a step of applying pressure onto the mandrel and the composite layup.

2. The method according to claim 1 , wherein the caul directly interfaces the non-planar portion of the composite layup.

3. The method according to claim 1 , wherein the step of heating the composite layup comprising a step of inductively heating a susceptor.

4. The method according to claim 1 , wherein:
the mandrel comprises thermal expansion slots,
the thermal expansion slots change widths during the step of heating the composite layup, and
the caul extends over at least one of the thermal expansion slots.

5. The method according to claim 1 , wherein the caul has a non-planar shape.

6. The method according to claim 1 , wherein the step of heating the composite layup forms a composite part from the composite layup.

7. The method according to claim 6 , wherein the composite part is one of a wing component comprising a stiffener, a flight control surface, or a fuselage door.

8. An induction heating cell comprising:
a die, configured to receive a composite layup;
an induction heater, configured to inductively heat the composite layup;
a caul, configured to position over and conform to the composite layup; and
a mandrel, configured to position over the caul, wherein a difference between a coefficient of thermal expansion (CTE) of the caul and a CTE of the composite layup is less than a difference between the CTE of the mandrel and the CTE of the caul.

9. The induction heating cell according to claim 8 , wherein the caul is susceptible to a magnetic field generated by the induction heater and configured to generate heat and indirectly heat the composite layup.

10. The induction heating cell according to claim 8 , wherein the induction heater comprises a susceptor for generating heat and heating the composite layup.

11. The induction heating cell according to claim 8 , wherein:
the mandrel comprises thermal expansion slots,
the mandrel is configured to change widths of the thermal expansion slots during thermal cycling, and
the caul extends over at least one of the thermal expansion slots.

12. The induction heating cell according to claim 11 , wherein the caul is a continuous sheet extending substantially an entire length of the mandrel and over all of the thermal expansion slots.

13. The induction heating cell according to claim 8 , wherein the mandrel comprises aluminum.

14. The induction heating cell according to claim 8 , wherein the caul is formed from an alloy comprising an iron.

15. The induction heating cell according to claim 14 , wherein the alloy further comprises nickel.

16. The induction heating cell according to claim 15 , wherein a concentration of nickel in the alloy is between about 30% atomic and 47% atomic.

17. The induction heating cell according to claim 15 , wherein the alloy further comprises cobalt.

18. The induction heating cell according to claim 17 , wherein:
a concentration of nickel in the alloy is between about 20% atomic and 40% atomic, and
a concentration of cobalt in the alloy is between about 10% atomic and 20% atomic.

19. The induction heating cell according to claim 8 , wherein the caul has a thickness of between about 0.3 millimeters and 0.7 millimeter.

20. The induction heating cell according to claim 8 , wherein the caul has a non-planar shape.

Assignees

• Boeing Co

Inventors

• Matsen Marc R
• Firth Lee C
• Foltz Gregory A
• Dykstra William C
• Noel Jennifer S

Classifications

• B29C70/549

  Details of caul plates, e.g. materials or shape · CPC title

• B29C33/06

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

• B29D99/0014

  provided with ridges or ribs, e.g. joined ribs · CPC title

• B29C35/0805 Primary

  using electromagnetic radiation · CPC title

• B29C70/44

  using isostatic pressure, e.g. pressure difference-moulding, vacuum bag-moulding, autoclave-moulding or expanding rubber-moulding · CPC title