Curing composites out-of-autoclave using induction heating with smart susceptors

• US 9,259,886 B2
• Filed: 09/29/2011
• Issued: 02/16/2016
• 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
• Primary Examiner(s): Ross, Dana
• Assistant Examiner(s): HARVEY, BRANDON T
• Application Number:
  US13/248,728
• Publication Number:
  US 20120145703A1
• Time in Patent Office: 1,601 Days
• Field of Search: 156/272.4, 219/601, 219/618, 219/622, 219/624, 219633-636, 219/645, 219/660, 219/662, 219/671, 219/672, 219/675, 219/676, 219/212, 392/469
• US Class Current: 1/1
• 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 tool base configured to receive the tool, the tool base having a hollowed out section configured to dissipate heat from the tool;

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 opposite the first side, the heating blanket comprising a flexible material and draped over an edge of the part to seal the heating blanket against the tool surface over the part so as to thermally enclose the part between the heating blanket and the tool surface;

a second inductive heating circuit within the heating blanket for heating the blanket, the second inductive heating circuit separated from the first inductive heating circuit; 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

the first and second heating circuits including 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 each of the induction coil circuits includes an induction coil and a smart susceptor having a preselected Curie temperature.

4. The apparatus of claim 3, wherein each of the induction coil circuits includes a tuning capacitor and is tuned to resonate at the frequency of the AC power supply.

5. The apparatus of claim 4, 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.

6. The apparatus of claim 3, 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.

7. The apparatus of claim 3, wherein the tool includes a layer of substantially rigid polymer resin encasing the first inductive heating circuit.

8. The apparatus of claim 7, wherein the rigid polymer resin is one of epoxy resin and bismaleimide resin.

9. The apparatus of claim 1, wherein the tool base is formed of a foam comprising one of silicone, rubber, or polyurethane.

10. 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.

11. The apparatus of claim 1, wherein the heating blanket is sealed against the tool surface substantially completely around the part.

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

a substantially rigid tool, the part positioned on the tool, 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 tool base configured to receive the tool, the tool base having a hollowed out section configured to dissipate heat from the tool;

a heating blanket adapted to be removably placed on the tool overlying the part opposite the first side, the heating blanket being flexible and conformable to a second side of the part and configured to drape over an edge of the part to seal the heating blanket against the tool surface over the part so as to thermally enclose the part between the heating blanket and the tool surface, the heating blanket including a second inductive heating circuit for heating the part, the second inductive heating circuit separated from the first inductive heating circuit;

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 polymer.

17. The apparatus of claim 16, wherein the polymer is a foam comprising one of silicone, rubber, and polyurethane 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. Stand-alone tooling for out-of-autoclave curing a composite aircraft part, comprising:

a tool base formed of a foam polymer comprising one of silicone, rubber, or polyurethane, 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, a part to be cured positioned on the tool surface;

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 temperature 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, the heating blanket comprising a flexible material and configured to drape over an edge of the part to seal the heating blanket against the tool surface over the part so as to thermally enclose the part between the heating blanket and the tool surface;

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 temperature 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.