Systems and methods for making indexed prepreg composite sheets and laminated composite articles

• US 9,724,845 B2
• Filed: 11/13/2014
• Issued: 08/08/2017
• Est. Priority Date: 11/13/2014
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Humfeld, Keith Daniel
• Primary Examiner(s): Chan, Sing P
• Application Number:
  US14/540,844
• Publication Number:
  US 20160263776A1
• Time in Patent Office: 999 Days
• Field of Search: 156228, 156230, 156231, 156237, 156238, 156246, 156247, 156249, 156250, 156263, 156267, 156269, 1562722, 1562728, 1562733, 156289, 1563071, 1563073, 1563074, 1563075, 1563077
• CPC Class Codes: B29B 11/12 Compression moulding
• CPC Class Codes: B29B 13/08 by using wave energy or particle radiation
• CPC Class Codes: B29B 15/12 of reinforcements of indefinite length
• CPC Class Codes: B29C 2793/0009 Cutting out
• CPC Class Codes: B29C 2793/0081 before shaping
• CPC Class Codes: B29C 70/545 Perforating, cutting or machining during or after moulding
• CPC Class Codes: B29K 2105/0872 Prepregs
• CPC Class Codes: B29K 2307/04 Carbon
• CPC Class Codes: B29K 2309/08 Glass

Abstract

A method of making an indexed prepreg composite sheet is disclosed. The method comprises forming discrete regions in a resin film layer. The discrete regions are arranged in an indexing pattern. The method also includes forming a precursor prepreg composite sheet by impregnating a fiber reinforcement with the resin film layer having a viscosity. The discrete regions of the resin film layer form non-impregnated regions of the precursor prepreg composite sheet. The method additionally includes replacing the non-impregnated regions of the precursor prepreg composite sheet with indexing openings.

Claims

1. A method of making an indexed prepreg composite sheet, the method comprising:

forming discrete regions in a resin film layer, wherein the discrete regions are arranged in an indexing pattern;

forming a precursor prepreg composite sheet by impregnating a fiber reinforcement with the resin film layer having a viscosity, wherein the discrete regions of the resin film layer form non-impregnated regions of the precursor prepreg composite sheet; and

replacing the non-impregnated regions of the precursor prepreg composite sheet with indexing openings.

2. The method according to claim 1, wherein forming the discrete regions in the resin film layer comprises forming hardened plugs by locally curing the resin film layer.

3. The method according to claim 2, wherein locally curing the resin film layer comprises locally irradiating the resin film layer with electromagnetic energy.

4. The method according to claim 2, wherein the hardened plugs correspond in size to the non-impregnated regions of the precursor prepreg composite sheet.

5. The method according to claim 2, wherein forming the precursor prepreg composite sheet further comprises locally penetrating the fiber reinforcement with the hardened plugs.

6. The method according to claim 2, wherein replacing the non-impregnated regions of the precursor prepreg composite sheet with the indexing openings comprises removing the hardened plugs from the precursor prepreg composite sheet.

7. The method according to claim 6, wherein removing the hardened plugs from the precursor prepreg composite sheet comprises pushing the hardened plugs out of the precursor prepreg composite sheet.

8. The method according claim 7, wherein the hardened plugs are pushed out of the precursor prepreg composite sheet using a pressurized fluid.

9. The method according to claim 6, wherein removing the hardened plugs from the precursor prepreg composite sheet comprises pulling the hardened plugs out of the precursor prepreg composite sheet.

10. The method according claim 9, wherein the hardened plugs are pulled out of the prepreg composite sheet using a vacuum.

11. The method according to claim 6, wherein removing the hardened plugs from the precursor prepreg composite sheet comprises applying heat to the resin film layer to decrease the viscosity of the resin film layer and removing the hardened plugs from the precursor prepreg composite sheet before the viscosity increases due to a formation of crosslinks in the resin film layer.

12. The method according to claim 1, wherein forming the discrete regions in the resin film layer comprises forming voids in the resin film layer.

13. The method according to claim 12, wherein the voids are larger than the non-impregnated regions of the precursor prepreg composite sheet.

14. The method according to claim 13, wherein forming the precursor prepreg composite sheet further comprises compressing the resin film layer to shrink the voids until the voids correspond in size to the non-impregnated regions of the precursor prepreg composite sheet.

15. The method according to claim 12, wherein:

the fiber reinforcement comprises fibers, and

replacing the non-impregnated regions of the precursor prepreg composite sheet with the indexing openings comprises removing the fibers from the non-impregnated regions of the precursor prepreg composite sheet.

16. The method according to claim 1, further comprising forming linear regions of weakness of the indexed prepreg composite sheet, wherein the linear regions of weakness define sub-sheets of the indexed prepreg composite sheet, each of the sub-sheets comprising a set of the indexing openings arranged in the indexing pattern.

17. The method according to claim 16, wherein forming the linear regions of weakness of the indexed prepreg composite sheet comprises forming linear separation regions in the resin film layer.

18. The method according to claim 17, wherein forming the linear separation regions in the resin film layer comprises forming discontinuous hardened strips in the resin film layer by locally curing the resin film layer.

19. The method according to claim 18, wherein forming the linear regions of weakness of the indexed prepreg composite sheet further comprises locally penetrating the fiber reinforcement with the discontinuous hardened strips when forming the precursor prepreg composite sheet.

20. The method according to claim 17, wherein forming the linear separation regions in the resin film layer comprises forming discontinuous gaps in the resin film layer.