Methods of manufacturing separable structures

• US 6,638,466 B1
• Filed: 12/28/2000
• Issued: 10/28/2003
• Est. Priority Date: 12/28/2000
• Status: Expired due to Fees

• Current Assignee: Beechcraft Corporation (Textron Inc)
• Original Assignee: Raytheon Aircraft Company (Textron Inc)
• Inventors: Abbott, Ric
• Primary Examiner(s): Staicovici, Stefan
• Application Number:
  US09/750,202
• Time in Patent Office: 1,034 Days
• Field of Search: 264/238, 264/264, 264/257, 264/258, 264/241, 264/255
• US Class Current: 264/238
• CPC Class Codes: B29C 33/68 Release sheets
• CPC Class Codes: B29C 70/46 using matched moulds, e.g. for deforming sheet moulding compounds [SMC] or prepregs
• CPC Class Codes: B29C 70/462 Moulding structures having an axis of symmetry or at least one channel, e.g. tubular structures, frames
• CPC Class Codes: B29C 70/48 and impregnating the reinforcements in the closed mould, e.g. resin transfer moulding [RTM] , e.g. by vacuum
• CPC Class Codes: B29C 70/54 Component parts, details or accessories; Auxiliary operations , e.g. feeding or storage of prepregs or SMC after impregnation or during ageing
• CPC Class Codes: B29L 2031/3085 Wings

Abstract

Methods for manufacturing composite material structures having one or more separable or replaceable skin portions. In one embodiment, the methods may include positioning first and second material pieces adjacent each other within a mold cavity and with a separating film disposed therebetween, introducing a first resin into the mold cavity to contact and substantially impregnate the first material piece with the first resin, and allowing the first resin to cure within the mold cavity to form a first part of the composite structure; and in which the separating film is substantially impermeable to the first resin.

Claims

1. A method of forming a composite structure, comprising:

positioning first and second material pieces adjacent each other within a mold cavity and with a separating film disposed between said first and second material pieces, said first material piece comprising an impregnable fiber material piece;

introducing a first resin into said mold cavity to contact and substantially impregnate said first material piece with said first resin;

allowing said first resin that substantially impregnates said first material piece to cure within said mold cavity to form a first part of said composite structure; and

wherein said separating film is substantially impermeable to said first resin;

wherein said second material piece comprises fiber material pre-impregnated with a second resin;

wherein said separating film is substantially impermeable to said second resin; and

wherein said method further comprises allowing said second resin to cure within said mold cavity to form a second part of said composite structure;

wherein said first and second resins substantially do not adhere to said separating film during said curing of said resins so that said separating film is substantially separable from each of said composite structure first and second parts; and

wherein said method further comprises;

removing said composite structure first and second parts from said mold cavity, separating said first and second composite structure parts from each other and removing said separating film, and then refitting said first and second composite structure parts together; and

forming an open area within a surface of said composite structure first part after separating said first and second composite structure parts;

wherein said open area is formed so as to be covered by said second composite structure part when said first and second composite structure parts are refitted together.

2. A method of forming a composite structure, comprising:

positioning first and second material pieces adjacent each other within a mold cavity and with a separating film disposed between said first and second material pieces, said first material piece comprising an impregnable fiber material piece;

introducing a first resin into said mold cavity to contact and substantially impregnate said first material piece with said first resin;

allowing said first resin that substantially impregnates said first material piece to cure within said mold cavity to form a first part of said composite structure; and

wherein said separating film is substantially impermeable to said first resin;

wherein said second material piece comprises fiber material;

wherein said separating film is substantially impermeable to said first resin; and

wherein said method further comprises introducing a second resin into said mold cavity to contact and substantially impregnate said second material piece with said second resin and allowing said second resin to cure within said mold cavity to form a second part of said composite structure;

wherein said first and second resins substantially do not adhere to said separating film during said curing of said resins so that said separating film is substantially separable from each of said composite structure first and second parts; and

wherein said method further comprises;

removing said composite structure first and second parts from said mold cavity, separating said first and second composite structure parts from each other and removing said separating film from between said first and second composite structure parts, and then refitting said first and second composite structure parts together;

forming an open area within a surface of said composite structure first part after separating said first and second composite structure parts;

wherein said open area is formed so as to be covered by said second composite structure part when said first and second composite structure parts are refitted together.

3. A method of forming a cured composite structure, comprising:

positioning a first material piece at least partially around an outer surface of at least one mandrel, said first material piece comprising a dry fiber material piece;

positioning a second material piece adjacent said first material piece with a separating film disposed therebetween to form an uncured composite structure;

positioning said uncured composite structure and said mandrel within a closed mold cavity;

introducing a first resin into said closed mold cavity to contact and at least partially impregnate said first material piece with said first resin;

allowing said first resin that at least partially impregnates said first material piece to cure within said mold cavity to form at least a portion of a cured composite substructure, said cured composite substructure and said second material piece together forming said cured composite structure;

removing said cured composite structure from said closed mold cavity; and

removing said mandrel from said cured composite substructure to form a hollow cured composite structure;

wherein said separating film is substantially impermeable to said first resin, and wherein said hollow cured composite substructure is substantially separable from said second material piece after removal from said closed mold cavity.

4. The method of claim 3, wherein said separating film is substantially separable from each of said hollow cured composite substructure and said second material piece after removal from said closed mold cavity;

and wherein said method further comprises separating said separating film from said first and second composite structure skins after removal of said composite structure from said mold cavity; and

then refitting said first and second composite structure skins together.

5. The method of claim 4, wherein said second material piece comprises fiber material pre-impregnated with a second resin;

wherein said separating film is substantially impermeable to said second resin; and

wherein said method further comprises allowing said second resin to cure within said mold cavity to form a cured composite structure skin of said cured composite structure.

6. The method of claim 3, wherein said separating film has opposing first and second surfaces;

and wherein said positioning of a second material piece adjacent said first material piece with a separating film disposed therebetween comprises positioning at least one surface of said first material piece in contact with said first surface of said separating film and positioning at least one surface of said second material piece in contact with said second surface of said separating film;

wherein said separating film substantially prevents said first resin from contacting said at least one surface of said second material piece that is in contact with said second surface of said separating film, and wherein said first resin substantially does not adhere to said separating film during said curing of said first resin so that said hollow cured composite substructure and said second material piece are substantially separable from each other after said first resin is cured and so that said separating film is substantially separable from each of said cured composite substructure and said second material piece after said first resin is cured; and

wherein said method further comprises separating said separating film from said hollow cured composite substructure and said second material piece after removal of said composite structure from said mold cavity, and then refitting together said hollow cured composite substructure and said second material piece.

7. The method of claim 6, wherein said second material piece comprises fiber material pre-impregnated with a second resin;

and wherein said method further comprises allowing said second resin to cure within said closed mold cavity to form a cured composite structure skin, wherein said separating film substantially prevents said second resin from contacting said at least one surface of said first fiber material piece that is in contact with said first surface of said separating film, and wherein said second resin substantially does not adhere to said separating film during said curing of said first and second resins so that said separating film is substantially separable from each of said hollow cured composite substructure and said cured composite structure skin after said first and second resins are cured; and

wherein said method further comprises separating said separating film from said hollow cured composite substructure and said cured composite structure skin after removal of said composite structure film said mold cavity, and then refitting together said hollow cured composite substructure and said cured composite structure skin.

8. The method of claim 6, wherein said second material piece comprises a second fiber material piece;

and wherein said method further comprises introducing a second resin into said closed mold cavity to contact and impregnate at least a portion of said second fiber material piece with said second resin; and

wherein said method further comprises allowing said second resin to cure within said closed mold cavity to form a cured composite structure skin, wherein said separating film substantially prevents said second resin from contacting said at least one surface of said first fiber material piece that is in contact with said first surface of said separating film, and wherein said second resin substantially does not adhere to said separating film during said curing of said first and second resins so that said separating film is substantially separable from each of said hollow cured composite substructure and said cured composite structure skin after said first and second resins are cured; and

wherein said method further comprises separating said separating film from said hollow cured composite substructure and said cured composite structure skin after removal of said composite structure from said mold cavity, and then refitting together said hollow cured composite substructure and said cured composite structure skin.

9. The method of claim 6, wherein at least:

said first material piece comprises one or more material pieces and wherein said at least one surface of said first material piece that is at least in partial contact with said first surface of said separating film has an integral open area defined therein between a first area of said first material piece and a second area of said first material piece; and

wherein said method further comprises positioning a resin transport film between at least a portion of said at least one surface of said first material piece and at least a portion of said first surface of said separating film so that said resin transport film is in a position effective to transport said introduced first resin from said first area of said first material piece across said open area to said second area of said first material piece;

or

wherein said method further comprises forming an open area within an area of said hollow cured composite substructure after separating said hollow cured composite substructure and said second material piece;

said open area corresponding to said at least one surface of said first material piece that is at least in partial contact with said first surface of said separating film during said curing; and

wherein said open area is formed so as to be covered by said second material piece when said hollow cured composite substructure and said second material piece are refitted together;

or

a combination thereof.

19. The method of claim 3, wherein said first resin comprises a thermosetting resin.

10. A method of forming a hollow cured composite aircraft structure using a single cure resin transfer molding process, comprising:

positioning a first fiber material piece at least partially around an outer surface of at least one mandrel, said first material piece comprising a dry fiber material piece;

positioning a second fiber material piece adjacent said first fiber material piece with a separating film disposed therebetween to form an uncured composite aircraft structure, wherein said separating film has opposing first and second surfaces, and wherein at least one surface of said first material piece is positioned in contact with said first surface of said separating film and at least one surface of said second material piece is positioned in contact with said second surface of said separating film;

positioning said uncured composite aircraft structure and said mandrel within a closed mold cavity;

introducing a first resin into said closed mold cavity to contact and at least partially impregnate said first fiber material piece with said first resin;

allowing said first resin that at least partially impregnates said first fiber material piece to cure within said mold cavity during a single cure cycle to form at least a portion of a cured composite aircraft substructure;

allowing a second resin that at least partially impregnates said second fiber material piece to cure within said mold cavity during said single cure cycle to form at least a portion of a cured composite aircraft structure skin, said cured composite aircraft substructure and said cured composite aircraft structure skin together forming a cured composite aircraft structure;

removing said cured composite aircraft structure from said closed mold cavity; and

removing said mandrel from said cured composite substructure to form said hollow cured composite aircraft structure;

wherein said separating film is substantially impermeable to said first and second resins so that said separating film substantially prevents said first resin from contacting said at least one surface of said second fiber material piece that is in contact with said second surface of said separating film, and wherein said separating film substantially prevents said second resin from contacting said at least one surface of said first fiber material piece that is in contact with said first surface of said separating film;

wherein said first resin substantially does not adhere to said separating film during said curing of said first resin, and wherein said second resin substantially does not adhere to said separating film during said curing of said second resin so that said cured composite aircraft substructure is substantially separable from said cured composite structure skin and so that said separating film is substantially separable from each of said cured composite aircraft substructure and said cured composite aircraft structure skin after said first and second resins arc cured and after removal of said cured composite aircraft structure from said closed mold cavity; and

wherein said method further comprises separating said separating film from said cured composite aircraft substructure and said cured composite aircraft structure skin after removal of said composite aircraft structure from said mold cavity, and then refitting together said hollow cured composite aircraft substructure and said cured composite aircraft structure skin.

11. The method of claim 10, wherein at least:

said first fiber material piece comprises one or more dry fiber material pieces and wherein said at least one surface of said first fiber material piece that is at least in partial contact with said first surface of said separating film has an integral open area defined therein between a first area of said first fiber material piece and a second area of said first fiber material piece; and

wherein said method further comprises positioning a resin transport film between at least a portion of sail at least one surface of said first fiber material piece and at least a portion of said first surface of said separating film so that said resin transport film is in a position effective to transport said introduced first resin from said first area of said first fiber material piece across said open area to said second area of said first fiber material piece;

or

wherein said method further comprises forming an open area within an area of said hollow cured composite aircraft substructure after separating said hollow cured composite aircraft substructure and said cured composite aircraft skin;

said open area corresponding to said at least one surface of said first fiber material piece that is at least in partial contact with said first surface of said separating film during said curing; and

wherein said open area is formed so as to be covered by said second fiber material piece when said hollow cured composite aircraft substructure and said second fiber material piece are refitted together;

or

a combination thereof.

12. The method of claim 10, wherein said first fiber material piece comprises braided carbon fiber sleeve material, woven carbon fiber material, knitted carbon fiber material, stitched carbon fiber composite material, fiber tape material, or a mixture thereof.

13. The method of claim 12, wherein said second fiber material piece comprises fiber material pre-impregnated with a second resin;

and wherein said method further comprises allowing said second resin to cure within said closed mold cavity during said single cure cycle to form said cured composite aircraft structure skin, wherein said separating film substantially prevents said second resin from contacting said at least one surface of said first fiber material piece that is in contact with said first surface of said separating film, and wherein said second resin substantially does not adhere to said separating film during said curing of said first and second resins so that said separating film is substantially separable from each of said hollow cured composite aircraft substructure and said cured composite aircraft structure skin after said first and second resins are cured; and

wherein said method further comprises separating said separating film from said hollow cured composite aircraft substructure and said cured composite aircraft structure skin after removal of said cured composite aircraft structure from said mold cavity, and then refitting together said hollow cured composite aircraft substructure and said cured composite aircraft structure skin.

14. The method of claim 13, wherein said separating film comprises at least one of tetrafluoroethylene-based material, polyvinyl fluoride-based material, or a mixture thereof.

15. The method of claim 14, wherein said second fiber material piece comprises a core of honeycomb material surrounded by one or more layers of resin-impregnated prepreg fiber material.

16. The method of claim 10, further comprising positioning at least one third fiber material piece at least partially around said outer surface of said at least one mandrel prior to positioning said first fiber material piece at least partially around said outer surface of said at least one mandrel so that said third fiber material piece is disposed between said outer surface of said mandrel and an inner surface of said first fiber material piece, said third fiber material comprising a dry fiber material piece;

and wherein said step of introducing a first resin into said closed mold cavity further comprises contacting and at least partially impregnating said third fiber material piece with said first resin; and

wherein said step of allowing said first resin to cure within said mold cavity comprises allowing said first resin that at least partially impregnates said third fiber material piece to cure within said mold cavity during said single cure cycle to form at least a portion of said cured composite aircraft substructure.

17. The method of claim 16, wherein said at least one mandrel comprises at least two mandrels;

and wherein said method further comprises positioning at least two respective third fiber material pieces at least partially around outer surfaces of said at least two respective mandrels and positioning said mandrels adjacent each other prior to positioning said first fiber material piece at least partially around said outer surface of said at least two mandrels so that said third fiber material piece is disposed between said outer surface of said mandrels and an inner surface of said first fiber material piece;

wherein said first fiber material forms an outer skin of said cured composite aircraft substructure, and wherein at least a portion of said third fiber material pieces form one or more spar sections of said cured composite aircraft substructure.

18. The method of claim 17, wherein said aircraft structure is an aircraft wing structure, an aircraft vertical stabilizer tail structure, or an aircraft horizontal stabilizer tail structure.

20. The method of claim 10, wherein said each of said first and second resins comprises a thermosetting resin.

21. A method of forming a composite structure, comprising:

positioning first and second material pieces adjacent each other within a mold cavity and with a separating film disposed between said first and second material pieces, said first material piece comprising an impregnable fiber material piece;

introducing a first resin into said mold cavity to contact and substantially impregnate said first material piece with said first resin;

allowing said first resin that substantially impregnates said first material piece to cure within said mold cavity to form a first part of said composite structure; and

wherein said separating film is substantially impermeable to said first resin;

wherein said second material piece comprises fiber material pre-impregnated with a second resin;

wherein said separating film is substantially impermeable to said second resin; and

wherein said method farther comprises allowing said second resin to cure within said mold cavity to form a second part of said composite structure; and

wherein said first and second resins substantially do not adhere to said separating film during said curing of said resins so that said separating film is substantially separable from each of said composite structure first and second parts; and

wherein said method further comprises removing said composite structure first and second parts from said mold cavity, separating said first and second composite structure parts from each other and removing said separating film, and then refitting said first and second composite structure parts together.

22. The method or claim 21, wherein said separating film substantially prevents said first resin from contacting said second material piece.

23. The method of claim 21, wherein said separating film has opposing first and second surfaces;

and wherein said positioning comprises positioning at least one surface of said first material piece in contact with said first surface of said separating film and positioning at least one surface of said second material piece in contact with said second surface of said separating film, wherein said separating film substantially prevents said first resin from contacting said at least one surface of said second material piece so that said composite structure first part and said second material pieces are substantially separable from each other after said first resin is cured.

24. A method of forming a composite structure, comprising;

positioning first and second material pieces adjacent each other within a mold cavity and with a separating film disposed between said first and second material pieces, said first material piece comprising an impregnable fiber material piece;

introducing a first resin into said mold cavity to contact and substantially impregnate said first material piece with said first resin;

allowing said first resin that substantially impregnates said first material piece to cure within said mold cavity to form a first part of said composite structure; and

wherein said separating film is substantially impermeable to said first resin;

wherein said second material piece comprises fiber material;

wherein said separating film is substantially impermeable to said first resin; and

wherein said method further comprises introducing a second resin into said mold cavity to contact and substantially impregnate said second material piece with said second resin and allowing said second resin to cure within said mold cavity to form a second part of said composite structure; and

wherein said first and second resins substantially do not adhere to said separating film during said curing of said resins so that said separating film is substantially separable from each of said composite structure first and second parts; and

wherein said method further comprises removing said composite structure first and second parts from said mold cavity, separating said first and second composite structure parts from each other and removing said separating film from between said first and second composite structure parts, and then refitting said first and second composite structure parts together.

25. A method of forming a composite structure, comprising:

positioning first and second material pieces adjacent each other within a mold cavity and with a separating film disposed between said first and second material pieces, said first material piece comprising an impregnable fiber material piece;

introducing a first resin into said mold cavity to contact and substantially impregnate said first material piece with said first resin wherein said separating film is substantially impregnable to said first resin;

allowing said first resin that substantially impregnates said first material piece to cure within said mold cavity to form a first part of said composite structure; and

wherein said first material piece comprises one or more material pieces and wherein at least one surface of said first material piece has an integral open area defined therein between a first area of said first material piece and a second area of said first material piece; and

wherein said positioning comprises positioning said at least one surface of said first material piece adjacent a first surface of said separating film with a resin transport film disposed therebetween so that said resin transport film is in a position effective to transport said introduced resin from said first area of said first material piece across said open area to said second area of said first material piece;

wherein said resin transport film comprises a dry fabric material.

26. A method of forming a composite structure, comprising:

positioning first and second material pieces adjacent each other within a mold cavity and with a separating film disposed between said first and second material pieces, said first material piece comprising an impregnable fiber material piece;

introducing a first resin into said mold cavity to contact and substantially impregnate said first material piece with said first resin;

allowing said first resin that substantially impregnates said first material piece to cure within said mold cavity to form a first part of said composite structure; and

wherein said separating film is substantially impermeable to said first resin;

wherein said first material piece comprises one or more material pieces and wherein at least one surface of said first material piece has an integral open area defined therein between a first area of said first material piece and a second area of said first material piece;

wherein said positioning comprises positioning said at least one surface of said first material piece adjacent a first surface of said separating film with a resin transport film disposed therebetween so that said resin transport film spans said integral open area between said first area of said first material piece and said second area of said first material piece to provide a resin transport path between said first area of said first material to said second area of said first material; and

wherein said method further comprises transporting said introduced resin by said resin transport path from said first area of said first material piece across said open area to said second area of said first material piece.