Machinable composite mold
View Patent ↗Machinable composite molds for use in making a composite structure. The mold includes a mold body having a tool surface that is shaped to provide the molded surface of the composite structure. The mold body is made up of at least one mold layer composed of a quasi-isotropic material composed of a plurality of randomly oriented fiber bundles or chips impregnated with a resin. The use of randomly oriented fiber chips allows post-cure machining of the mold body.
1. A mold for use in making a composite structure wherein said composite structure has a molded surface, said mold comprising:
a mold body comprising a tool surface which is shaped to provide said molded surface of said composite structure, said mold body comprising at least one mold layer comprising a quasi-isotropic material comprising a plurality of randomly oriented rectangular chips comprising fibers and a resin, said mold layer comprising a surface that forms at least a part of said tool surface.
2. A mold for use in making a composite structure according to claim 1 wherein said resin comprises bismaleimide resin and said fibers comprise carbon fibers.
3. A mold for use in making a composite structure according to claim 1 wherein at least two mold layers are used to form said mold body.
4. A mold for use in making a composite structure according to claim 3 wherein said tool surface extends across at least a portion of two adjacent mold layers.
5. A mold for use in making a composite structure according to claim 1 wherein at least a portion of said tool surface is formed by machining at least a portion the surface of said mold layer.
6. A mold for use in making a composite structure according to claim 4 wherein at least a portion of said two adjacent mold layers are machined to provide said tool surface that extends across at least a portion of each of said adjacent mold layers.
7. A mold for use in making a composite structure according to claim 1 wherein said fibers comprise unidirectional fibers or woven fibers.
8. A mold for use in making a composite structure according to claim 2 wherein said fibers comprise unidirectional fibers or woven fibers.
9. A mold for use in making a composite structure according to claim 1 wherein said fibers comprise unidirectional fibers.
10. A mold for use in making a composite structure according to claim 2 wherein said fibers comprise unidirectional fibers.
11. A mold for use in making a composite structure according to claim 1 wherein said rectangular chips are from ½ inch to 4 inches long and from ⅛ inch to 1 inch wide.
12. A mold for use in making a composite structure according to claim 2 wherein said rectangular chips are from ½ inch to 4 inches long and from ⅛ inch to 1 inch wide.
13. A mold for use in making a composite structure according to claim 1 wherein said chip comprises from 1,000 to 100,000 fibers.
14. A mold for use in making a composite structure according to claim 2 wherein said chip comprises from 1,000 to 100,000 fibers.
15. A mold for use in making a composite structure according to claim 1 wherein said resin comprises from 30 to 50 volume percent of said chips.
16. A mold for use in making a composite structure according to claim 2 wherein said resin comprises from 30 to 50 volume percent of said chips.
17. A mold for use in making a composite structure according to claim 5 wherein said portion of said tool surface that is formed by machining has a surface contour deviation of less than ±0.003 inch.
18. A mold for use in making a composite structure according to claim 6 wherein said portion of said tool surface that is formed by machining has a surface contour deviation of less than ±0.003 inch.
19. A mold for use in making a composite structure according to claim 17 wherein said resin comprises bismaleimide resin and said fibers comprise carbon fibers.
20. A mold for use in making a composite structure according to claim 18 wherein said resin comprises bismaleimide resin and said fibers comprise carbon fibers.