Methods of forming a thinned prepreg sheet

Patent metadata

Field	Value
Publication number	US-9604414-B2
Application number	US-201414549231-A
Country	US
Kind code	B2
Filing date	Nov 20, 2014
Priority date	Nov 20, 2014
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

A method of forming a thinned prepreg sheet is disclosed. The method comprises providing a first precursor sheet comprising reinforcement fibers impregnated with a matrix resin in a first state. The method also comprises forming a second precursor sheet having a first thickness by cooling the first precursor sheet until the matrix resin is transformed from the first state to a second state. The method further comprises forming a crushed sheet comprising interstices having an average size by crushing the second precursor sheet, where the crushed sheet has a second thickness. The method also comprises forming the thinned prepreg sheet by heating the crushed sheet until the matrix resin is transformed from the second state to a third state. The thinned prepreg sheet has a third thickness less than the first thickness of the second precursor sheet.

First claim

What is claimed is:

1. A method ( 200 ) of forming a thinned prepreg sheet ( 100 ), the method comprising:
providing a first precursor sheet ( 102 ) comprising reinforcement fibers ( 104 ) impregnated with a matrix resin ( 106 ) in a first state;
forming a second precursor sheet ( 110 ) having a first thickness ( 112 ) by cooling the first precursor sheet ( 102 ) until the matrix resin ( 106 ) is transformed from the first state to a second state;
forming a crushed sheet ( 120 ) comprising interstices ( 128 ) having an average size, wherein the crushed sheet ( 120 ) has a second thickness ( 122 ), by crushing the second precursor sheet ( 110 ); and
forming the thinned prepreg sheet ( 100 ), wherein the thinned prepreg sheet ( 100 ) has a third thickness ( 132 ) less than the first thickness ( 112 ) of the second precursor sheet ( 110 ), by heating the crushed sheet ( 120 ) until the matrix resin ( 106 ) is transformed from the second state to a third state.

2. The method ( 200 ) according to claim 1 , wherein, in the first state, the matrix resin ( 106 ) is uncured.

3. The method ( 200 ) according to claim 1 , wherein providing the first precursor sheet ( 102 ) comprises impregnating the reinforcement fibers ( 104 ) with the matrix resin ( 106 ) in the first state.

4. The method ( 200 ) according to claim 3 , wherein, in the first state, the matrix resin ( 106 ) is sufficiently flowable to impregnate the reinforcement fibers ( 104 ).

5. The method ( 200 ) according to claim 1 , wherein providing the first precursor sheet ( 102 ) comprises providing a prepreg sheet.

6. The method ( 200 ) according to claim 5 , wherein, in the first state, the matrix resin ( 106 ) is partially cured.

7. The method ( 200 ) according to claim 1 , wherein, in the second state, the matrix resin ( 106 ) is crushable.

8. The method ( 200 ) according to claim 1 , wherein, in the third state, the matrix resin ( 106 ) is sufficiently flowable to fill the interstices ( 128 ) of the crushed sheet ( 120 ).

9. The method ( 200 ) according to claim 1 , wherein cooling the first precursor sheet ( 102 ) until the matrix resin ( 106 ) is transformed from the first state to the second state comprises freezing the first precursor sheet ( 102 ).

10. The method ( 200 ) according to claim 1 , wherein forming the crushed sheet ( 120 ) further comprises crushing the second precursor sheet ( 110 ) into fragments ( 126 ) partially separated by the interstices ( 128 ).

11. The method ( 200 ) according to claim 10 , wherein forming the crushed sheet ( 120 ) further comprises spreading the fragments ( 126 ) of the second precursor sheet ( 110 ) along a plane.

12. The method ( 200 ) according to claim 11 , wherein spreading the fragments ( 126 ) of the second precursor sheet ( 110 ) along the plane comprises maintaining the average size of the interstices ( 128 ) between the fragments ( 126 ).

13. The method ( 200 ) according to claim 10 , wherein spreading the fragments ( 126 ) of the second precursor sheet ( 110 ) along the plane comprises vibrating the fragments ( 126 ).

14. The method ( 200 ) according to claim 10 , wherein forming the crushed sheet ( 120 ) further comprises applying a compressive force to the second precursor sheet ( 110 ) with a press ( 130 ).

15. The method ( 200 ) according to claim 14 , wherein forming the crushed sheet ( 120 ) further comprises vibrating the press ( 130 ).

16. The method ( 200 ) according to claim 14 , wherein forming the crushed sheet ( 120 ) further comprises advancing the press ( 130 ) along a surface ( 136 ) of the second precursor sheet ( 110 ).

17. The method ( 200 ) according to claim 16 , wherein advancing the press ( 130 ) along the surface ( 136 ) of the second precursor sheet ( 110 ) comprises rolling the press ( 130 ) along the surface ( 136 ).

18. The method ( 200 ) according to claim 1 , wherein heating the crushed sheet ( 120 ) comprises melting the matrix resin ( 106 ) of the crushed sheet ( 120 ).

19. The method ( 200 ) according to claim 1 , wherein heating the crushed sheet ( 120 ) comprises consolidating the crushed sheet ( 120 ).

20. The method ( 200 ) according to claim 1 , wherein heating the crushed sheet ( 120 ) comprises filling the interstices ( 128 ) in the crushed sheet ( 120 ) with the matrix resin ( 106 ) of the crushed sheet ( 120 ).

Assignees

• Boeing Co

Inventors

• Humfeld Keith Daniel

Classifications

• B32B38/08

  Impregnating · CPC title

• B32B2305/076

  Prepregs · CPC title

• B32B2038/0024

  Crushing · CPC title

• B32B37/08 Primary

  characterised by the cooling method · CPC title

• B29C70/506

  and impregnating by melting a solid material, e.g. sheet, powder, fibres (B29C70/508 takes precedence) · CPC title