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

Patent metadata

Field	Value
Publication number	US-9724845-B2
Application number	US-201414540844-A
Country	US
Kind code	B2
Filing date	Nov 13, 2014
Priority date	Nov 13, 2014
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

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.

First claim

What is claimed is:

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.

Assignees

• Boeing Co

Inventors

• Humfeld Keith Daniel

Classifications

• B29C70/545

  Perforating, cutting or machining during or after moulding · CPC title

• B29B15/12 Primary

  of reinforcements of indefinite length · CPC title

• B29B11/12 Primary

  Compression moulding · CPC title

• B29C2793/0081

  before shaping · CPC title

• B29C2793/0009

  Cutting out · CPC title