Curing Composites Out-Of-Autoclave Using Induction Heating with Smart Susceptors

• US 20120145703A1
• Filed: 09/29/2011
• Published: 06/14/2012
• Est. Priority Date: 12/15/2009
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Matsen, Marc Rollo, Miller, Robert James, Negley, Mark Alan, Noel, Jennifer Sue
• Granted Patent: US 9,259,886 B2
• Time in Patent Office: Days
• US Class Current: 219/618
• CPC Class Codes: B29C 2035/0811 using induction
• CPC Class Codes: B29C 2035/0816 using eddy currents
• CPC Class Codes: B29C 35/00 Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor moulds with incorporated heating or cooling means B29C33/02 ; thermal after-treatment of shaped articles B29C71/02; curing devices for plastics dental prostheses A61C13/14; before moulding B29B13/00
• CPC Class Codes: B29C 73/10 using patches sealing on the surface of the article B29C73/14 takes precedence
• CPC Class Codes: B29C 73/30 for local pressing or local heating
• CPC Class Codes: B29C 73/34 for local heating
• CPC Class Codes: B29K 2063/00 Use of EP, i.e. epoxy resins or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2105/12 of short lengths, e.g. chopped filaments, staple fibres or bristles
• CPC Class Codes: B29K 2105/253 Preform
• CPC Class Codes: B29K 2307/04 Carbon
• 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 6/06 Control, e.g. of temperature, of power
• CPC Class Codes: H05B 6/105 using a susceptor
• CPC Class Codes: H05B 6/106 in the form of fillings
• CPC Class Codes: H05B 6/36 Coil arrangements

Abstract

A composite part is cured out-of-autoclave using an inductively heated, stand-alone tooling. The part in placed on a tool and is covered by a heating blanket. One side of the part is heated by inductive coil circuits in the tool, and the other side of the part is heated by inductive coil circuits in the blanket.

Claims

1. Apparatus for curing a composite part, comprising:

a tool having a tool surface adapted to engage a first side of the part;

a first inductive heating circuit within the tool for heating the tool surface;

a heating blanket adapted to be placed over a second side of the part;

a second inductive heating circuit within the heating blanket for heating the blanket; and

an electrical power supply coupled with the first and second inductive heating circuits.

2. The apparatus of claim 1, wherein:

the power supply is an AC power supply; and

at least one of the first and second heating circuits includes a plurality of induction coil circuits electrically coupled in parallel with each other and in series with the AC power supply.

3. The apparatus of claim 2, wherein:

the other of the first and second heating circuits includes a plurality of induction coil circuits electrically coupled in parallel with each other and in series with the AC power supply.

4. The apparatus of claim 2, wherein each of the induction coil circuits includes an induction coil and a smart susceptor having a preselected Curie temperature.

5. The apparatus of claim 4, wherein each of the induction coil circuits includes a tuning capacitor and is tuned to resonant at the frequency of the AC power supply.

6. The apparatus of claim 5, wherein the capacitor has a value of capacitance forming capacitive reactance that is substantially equal to the inductive reactance of the associated induction coil circuit when the susceptor is below its Curie temperature.

7. The apparatus of claim 4, further comprising:

a controller for controlling the AC power supply to redistribute power supplied to the induction coil circuits when one or more of the susceptors reaches its Curie temperature.

8. The apparatus of claim 4, wherein the tool includes a layer of substantially rigid polymer resin encasing the first inductive heating circuit.

9. The apparatus of claim 8, wherein the rigid polymer resin is one of epoxy resin and bismaleimide resin.

10. The apparatus of claim 1, wherein the tool includes a tool base formed of a high temperature foam and hollowed out to dissipate heat from the tool.

11. The apparatus of claim 1, wherein the heating blanket is formed of a generally flexible elastomer allowing the heating blanket to conform to the second side of the part.

12. Apparatus for out-of-autoclave curing of a composite part, comprising:

a substantially rigid tool on which the part may be placed, the tool including a tool surface substantially matching and contacting a first side of the part, the tool further including a first induction heating circuit for heating the part;

a heating blanket adapted to be removably placed on the tool overlying the part, the heating blanket being flexible and conformable to a second side of the part, the heating blanket including a second inductive heating circuit for heating the part;

at least one of the first and second inductive heating circuits including at least two induction coil circuits electrically coupled in series with each other, each of the induction coil circuits including an inductive coil and a susceptor coupled with the coil and having a Curie temperature; and

an AC power supply electrically coupled in series with the induction coil circuits.

13. The apparatus of claim 12, wherein each of the induction heating circuits includes a capacitor for tuning the resonant frequency of the circuit to substantially match the frequency of the AC power supply.

14. The apparatus of claim 12, wherein the tool includes a layer of substantially rigid polymer resin encasing the first inductive heating circuit.

15. The apparatus of claim 14, wherein the rigid polymer resin is one of epoxy resin and bismaleimide resin.

16. The apparatus of claim 14, wherein the tool includes a tool base supporting the layer of rigid polymer resin and formed of a high temperature polymer.

17. The apparatus of claim 16, wherein the high temperature polymer is a foam and the tool base includes a hollowed-out portion to dissipate heat from the tool.

18. The apparatus of claim 12, wherein the heating blanket is formed of a generally flexible elastomer allowing the heating blanket to conform to the second side of the part.

19. The apparatus of claim 12, wherein the heating blanket includes:

a pair of flexible facesheets; and

a thermally conductive matrix between the facesheets for conducting heat to the part.

20. The apparatus of claim 12, wherein the tool includes:

a tool base having a recess therein; and

a layer of substantially rigid polymer resin located in the recess and encasing the first inductive heating circuit.

21. A method of out-of-autoclave curing a composite part, comprising:

placing a part to be cured on a substantially rigid tool;

heating a first side of the part by inductively heating the tool;

placing a heating blanket on a second side of the part; and

using the heating blanket to heat the part from the second side thereof.

22. The method of claim 21, wherein inductively heating the tool includes:

flowing electrical current through at least one conductor passing through the tool;

using the electrical current flow to heat a susceptor within the tool; and

conducting heat from the susceptor through a matrix in the blanket to a surface of the tool in contact with the first side of the part.

23. The method of claim 21, wherein inductively heating the tool includes:

coupling a plurality of inductive coil circuits in parallel with each other, wherein each of the circuits includes an inductive coil and a susceptor having a Curie temperature;

driving each of the circuits with an alternating electrical current;

shunting power away from one of the circuits when the susceptor in the circuit reaches its Curie temperature.

24. Stand-alone tooling for out-of-autoclave curing a composite aircraft part, comprising:

a tool base formed of a high temperature foam polymer, the tool base including a hollowed out side for dissipating heat and a tool supporting side provided with a recess therein;

a tool supported on the tool base and located within the recess thereof, the tool including a rigid layer of a polymer resin and having a tool surface on which a part to be cured may be placed;

a plurality of first induction coil circuits embedded within the rigid polymer layer and electrically coupled in parallel with each other for heating one side of the part, each of the first induction coil circuits including

an induction heating coil,

a susceptor having a preselected Curie point inductively coupled with the coil, and

a capacitor for tuning the resonant frequency of the circuit,

a flexible heating blanket adapted to be removably placed on the tool covering and conforming to the part, the heating blanket including a pair of elastomeric facesheets and a thermally conductive matrix between the first and second facesheets for conducting heat to the part;

a plurality of second induction coil circuits embedded within the matrix and electrically coupled in parallel with each other for heating one side of the part, each of the second induction coil circuits including

an induction heating coil;

a susceptor having a preselected Curie point inductively coupled with the coil; and

a capacitor for tuning the resonant frequency of the circuit; and

an AC power supply coupled in series with the plurality of first induction coil circuits for supplying alternating current to each of the coils in the first circuits, the AC power supply being coupled in series with the plurality of second induction coil circuits for supplying alternating current to each of the coils in the second circuits.

25. An out-of-autoclave method of curing of a composite aircraft part, comprising:

fabricating a cure tool by encasing a plurality of first induction heating coil circuits in a layer of rigid polymer resin, including coupling the first induction heating coil circuits in parallel with each other, each of the first induction heating coil circuits including an induction coil and a susceptor having a Curie temperature;

supporting the tool on a tool base;

hollowing out one side of the tool base to dissipate heat used to cure the part;

placing a part to be cured on the tool with a first side of the part in contact with the rigid layer of polymer resin;

heating the first side of the part using the tool, including using the plurality of first induction heating coil circuits to heat the polymer layer and shunting power away from at least one of the first induction heating coil circuits to the other of the first induction heating coil circuits when the susceptor in the circuit reaches its Curie temperature;

fabricating a flexible heating blanket by embedding a plurality of second induction heating coil circuits in a thermally conductive elastomeric matrix, each of the second induction heating coil circuits including an induction coil and a susceptor having a Curie temperature;

placing the heating blanket on the tool and in contact with a second side of the part, including conforming the heating blanket to the second side of the part;

coupling an AC power supply in series with the plurality of first induction heating coil circuits and in series with the plurality of second induction heating coil circuits; and

using the heating blanket to heat the second side of the part including using the plurality of second induction heating coil circuits to heat the matrix, and shunting power away from at least one of the second induction heating coil circuits to the other of the second induction coil heating circuits when the susceptor in the circuit reaches its Curie temperature.