Method of manufacturing a composite workpiece

Patent metadata

Field	Value
Publication number	US-11325282-B2
Application number	US-201916459505-A
Country	US
Kind code	B2
Filing date	Jul 1, 2019
Priority date	Jul 1, 2019
Publication date	May 10, 2022
Grant date	May 10, 2022

Abstract

Methods of manufacturing composite workpieces that include positioning a heat-generating element proximate to an uncured composite workpiece, triggering the heat-generating element to produce an exothermic chemical reaction or exothermic physical reaction so that the temperature of the uncured composite workpiece is raised to a predetermined first temperature, and curing the composite workpiece while it is at a temperature that is at least the predetermined first temperature.

First claim

What is claimed is:

1. A method of manufacturing a composite workpiece, the method comprising:
positioning a heat-generating element and a plurality of thermally expandable pellets proximate to an uncured composite workpiece, the heat-generating element being capable of undergoing an exothermic chemical reaction or an exothermic physical reaction when triggered, the plurality of thermally expandable pellets being configured to soften and undergo volumetric expansion by foaming when heated to a predetermined first temperature;
constraining a volume around the uncured composite workpiece;
triggering the heat-generating element to produce the exothermic chemical reaction or the exothermic physical reaction so that a temperature of the uncured composite workpiece and the plurality of thermally expandable pellets is raised to at least the predetermined first temperature, and so that the plurality of thermally expandable pellets undergoes the volumetric expansion by foaming to apply at least a predetermined pressure to the composite workpiece; and
curing the composite workpiece while the composite workpiece is at a temperature that is at least the predetermined first temperature and while at least the predetermined pressure is applied to the composite workpiece.

2. The method of claim 1 , wherein positioning includes positioning a mixture of the heat-generating element and the plurality of thermally expandable pellets proximate to the uncured composite workpiece.

3. The method of claim 1 , wherein positioning the heat-generating element proximate to the uncured composite workpiece includes positioning a heat-generating element configured to undergo an exothermic physical reaction that is an exothermic change of state; and triggering the heat-generating element includes triggering the exothermic change of state.

4. The method of claim 1 , wherein positioning the heat-generating element proximate to the uncured composite workpiece includes positioning a heat-generating element configured to undergo an exothermic chemical reaction; and triggering the heat-generating element includes triggering the exothermic chemical reaction.

5. The method of claim 1 , wherein positioning the heat-generating element proximate to the uncured composite workpiece includes positioning a mixture of the heat-generating element and a heating mediation agent proximate to the uncured composite workpiece, and wherein the heating mediation agent undergoes an endothermic physical reaction or an endothermic chemical reaction to decrease a maximum temperature reached proximate the composite workpiece after triggering the heat-generating element.

6. The method of claim 1 , further comprising removing the heat-generating element after the composite workpiece is cured.

7. The method of claim 6 , wherein removing the heat-generating element includes cooling the heat-generating element to a second temperature lower than the predetermined first temperature, or allowing the heat-generating element to cool to a second temperature lower than the predetermined first temperature.

8. The method of claim 1 , further comprising applying a removable barrier film to an outer surface of the uncured composite workpiece before positioning the heat-generating element proximate to the uncured composite workpiece.

9. The method of claim 1 , wherein the heat-generating element has the form of a plurality of pellets.

10. The method of claim 9 , wherein the plurality of pellets forming the heat-generating element is not substantially sintered after the heat-generating element is triggered.

11. The method of claim 9 , wherein the plurality of pellets forming the heat-generating element are contained within one or more flexible bags, and positioning the heat-generating element proximate to the uncured composite workpiece includes positioning the one or more flexible bags proximate to the uncured composite workpiece.

12. The method of claim 11 , wherein the one or more flexible bags further contain a pelletized heating mediation agent and/or the plurality of thermally expandable pellets; and positioning the heat-generating element proximate to the uncured composite workpiece includes placing one or more such flexible bags proximate to the uncured composite workpiece.

13. The method of claim 1 , wherein constraining is performed using a constraining container, and wherein thermally expandable pellets of the plurality of thermally expandable pellets are in direct contact with a wall of the constraining container after the plurality of thermally expandable pellets have undergone the volumetric expansion by foaming.

14. The method of claim 1 , wherein positioning includes disposing the heat-generating element above, beneath, and around the uncured composite workpiece.

15. The method of claim 14 , wherein the heat-generating element includes a plurality of heat-generating pellets, and wherein positioning includes disposing the plurality of heat-generating pellets above, beneath, and around the uncured composite workpiece.

16. The method of claim 1 , wherein the plurality of thermally expandable pellets includes a thermoplastic material having a glass transition temperature and a melting temperature, and wherein triggering includes heating the plurality of thermally expandable pellets to a maximum temperature that is above the glass transition temperature and below the melting temperature.

17. A method of manufacturing a composite aircraft component, the method comprising:
positioning a mixture of a heat-generating element and a heating mediation agent proximate to an uncured composite aircraft component, the heat-generating element being capable of undergoing an exothermic chemical reaction or an exothermic physical reaction when triggered; and
triggering the heat-generating element to produce the exothermic chemical reaction or the exothermic physical reaction so that a temperature of the uncured composite aircraft component is raised to at least a predetermined first temperature at which the uncured composite aircraft component will be cured; and
wherein the heating mediation agent undergoes an endothermic physical reaction or an endothermic chemical reaction to decrease a maximum temperature reached proximate the composite aircraft component after triggering the heat-generating element.

18. The method of claim 17 , further comprising positioning a thermally-expanding element proximate to the uncured composite aircraft component so that triggering the heat-generating element additionally triggers the thermally-expanding element to undergo a volumetric expansion and apply pressure to the uncured composite aircraft component while it is curing.

19. The method of claim 17 , wherein the heat-generating element is pelletized, and positioning the heat-generating element proximate to the uncured composite aircraft component includes placing one or more flexible bags containing the pelletized heat-generating element proximate to the uncured composite aircraft component.

20. The method of claim 19 , the one or more flexible bags further include a pelletized heating mediation agent and/or a pelletized thermally-expanding element.

Assignees

• Boeing Co

Inventors

• Wang Xiaoxi
• Georgeson Gary Ernest
• Santiago Jonathan A

Classifications

• B29C35/02 Primary

  Heating or curing, e.g. crosslinking or vulcanizing {during moulding, e.g. in a mould}(cold vulcanisation B29C35/18 {; vulcanising tyres, presses therefor B29D30/0601}) · CPC title

• B29L2031/3076

  Aircrafts (blades, propellers B29L2031/08) · CPC title

• B29C61/04

  Thermal expansion · CPC title

• B29C43/3642

  Bags, bleeder sheets or cauls for isostatic pressing · CPC title

• B29C2043/561

  under vacuum conditions · CPC title