Resin film infusion process and apparatus

{
  "publication_number": "US4622091A",
  "country": "US",
  "kind": "A",
  "title": "Resin film infusion process and apparatus",
  "abstract": "A method and apparatus for creating monolithic structures formed of fiber reinforced resin composites, i.e., layers or plies bonded together by a cured resin is disclosed. A plurality of dry plies (13, 15, 17, 19) are stacked to create a dry preform (11). The orientation of the plies is based on the desired directional strength of the resulting structure. The plies may or may not be stitched in the cross-ply direction, as desired. After the dry preform (11) is created, one or more layers of liquid or solid resin (21) are added. The dry preform and the resin layer(s), which are located atop a forming tool (33), are enclosed by resin content control envelope (35) through which breather tape (49) passes. The resin content control envelope (35) is, in turn, enclosed by a vacuum envelope (37). First air and other gases are withdrawn and, then, the composite is heated, causing the resin to flow into the dry preform (11). As the resin (21) enters the dry preform (11), air and other gases remaining in the dry preform (or created as the resin cures) are withdrawn via the conduit created by the dry preform fibers and various regions of breather tape (45, 49, 63).",
  "claims": [
    "1. A method of forming fiber reinforced resin composites comprising the steps of: creating a dry preform of at least two dry fiber plies, each of said dry fiber plies formed of a plurality of reinforcement fibers; adding at least one layer of resin to said dry preform; enclosing said dry preform and said at least one layer of resin in a resin content control envelope; enclosing said resin content control envelope in a vacuum envelope; evacuating said vacuum envelope and said resin content control envelope to withdraw air and other gases from said dry preform; and, heating said dry preform and said at least one layer of resin simultaneously with the evacuation of said vacuum envelope and said resin content control envelope to cause said resin to melt, fully infuse said dry preform and, then, cure as air and other gases are withdrawn from said dry preform resulting in the creation of a fiber reinforced resin composite.",
    "2. The method claimed in claim 1 wherein said at least one layer of resin is formed of a plurality of tiles.",
    "3. The method claimed in claim 2 wherein said plurality of tiles are supported by a scrim cloth.",
    "4. The method claimed in claim 1 wherein each of said fiber plies is formed of a plurality of parallel oriented tows, each tow formed of a plurality of unidirectional reinforcement fibers.",
    "5. The method claimed in claim 1 including the steps of: creating a second dry preform of at least two dry fiber plies, each of said fiber plies formed of a plurality of reinforcement fibers; and, positioning said second dry preform atop said dry preform.",
    "6. The method claimed in claim 5 wherein said at least one layer of resin is formed of a plurality of tiles.",
    "7. The method claimed in claim 6 wherein said plurality of tiles are supported by a scrim cloth.",
    "8. The method claimed in claim 5 wherein each of said dry fiber plies is formed of a plurality of parallel oriented tows, each tow formed of a plurality of unidirectional reinforcement fibers.",
    "9. The method claimed in claim 5 including the step of adding a second layer of resin to said dry preform.",
    "10. The method claimed in claim 9 wherein said layers of resin are formed of a plurality of tiles.",
    "11. The method claimed in claim 10 wherein said plurality of tiles are supported by a scrim cloth.",
    "12. The method claimed in claim 9 wherein each of said dry fiber plies is formed of a plurality of parallel oriented tows, each tow formed of a plurality of unidirectional reinforcement fibers.",
    "13. The method claimed in claim 9 including the step of positioning a core between said dry preform and said second dry preform.",
    "14. The method claimed in claim 13 wherein said layers of resin are formed of a plurality of tiles.",
    "15. The method claimed in claim 14 wherein said plurality of tiles are supported by a scrim cloth.",
    "16. The method claimed in claim 13 wherein each of said dry fiber plies is formed of a plurality of parallel oriented tows, each tow formed of a plurality of unidirectional reinforcement fibers.",
    "17. The method claimed in claim 13 wherein said core is a honeycomb core.",
    "18. The method claimed in claim 1 including a step of creating a plurality of stacks of preform doubler plies atop said dry preform.",
    "19. The method claimed in claim 18 wherein said at least one layer of resin is formed of a plurality of tiles.",
    "20. The method claimed in claim 19 wherein said plurality of tiles are supported by a scrim cloth.",
    "21. The method claimed in claim 18 wherein each of said dry fiber plies is formed of a plurality of parallel oriented tows, each tow formed of a plurality of unidirectional reinforcement fibers.",
    "22. The method claimed in claim 1 including the step of positioning a lower release film beneath said dry preform and said at least one layer of resin, said lower release film forming part of said resin content control envelope.",
    "23. The method claimed in claim 22 including the step of positioning an upper release film atop said dry preform, said upper release film also forming part of said resin content control envelope.",
    "24. The method claimed in claim 23 wherein said at least one layer of resin is located between said upper release film and said dry preform.",
    "25. The method claimed in claim 24 wherein said upper and lower release films are joined by vacuum sealer tape located around the periphery of said dry preform.",
    "26. The method claimed in claim 25 including the step of positioning at least one layer of inner breather tape adjacent to said dry preform, inside of said resin content control envelope.",
    "27. The method claimed in claim 26 including the step of positioning at least one layer of vacuum port breather tape between said upper and lower release films and across said vacuum sealer tape that joins said upper and lower release films to provide a gas conduit between said inner breather tape and the exterior of said resin content control envelope.",
    "28. The method claimed in claim 23 including a perforated release film located between said at least one layer of resin and said dry preform.",
    "29. The method claimed in claim 28 wherein said upper and lower release films are joined by vacuum sealer tape located around the periphery of said dry preform.",
    "30. The method claimed in claim 29 including the step of positioning at least one layer of inner breather tape adjacent to said dry preform, inside of said resin content control envelope.",
    "31. The method claimed in claim 30 including the step of positioning at least one layer of vacuum port breather tape between said upper and lower release films and across said vacuum sealer tape that joins said upper and lower release films to provide a gas conduit between said inner breather tape and the exterior of said resin content control envelope.",
    "32. The method claimed in claim 23 including the step of positioning said lower release film atop a lower tool.",
    "33. The method claimed in claim 32 including the step of positioning an upper tool atop said dry preform.",
    "34. The method claimed in claim 33 wherein said at least one layer of resin is located between said upper tool and said dry preform.",
    "35. The method claimed in claim 34 wherein said upper release film is located between said upper tool and said at least one layer of resin.",
    "36. The method claimed in claim 33 wherein said upper tool is perforated and located between said at least one layer of resin and said dry preform.",
    "37. The method claimed in claim 36 including a perforated release film located between said upper tool and said dry preform.",
    "38. Apparatus for creating monolithic structures formed of layers of plies joined by a cured resin, said apparatus comprising: (a) a vacuum envelope including first conduit means for connecting said vacuum envelope to a vacuum source, said vacuum envelope comprising: (i) a lower tool; (ii) a gas impervious layer; and, (iii) vacuum attachment means for attaching said gas impervious layer to said lower tool such that a vacuum envelope is formed between said gas impervious layer and said lower tool; (b) a resin content control envelope positioned within said vacuum envelope for enclosing a monolithic structure as it is being formed, said monolithic structure created from a dry preform formed of a plurality of dry plies and at least one layer of resin, said resin content control envelope comprising: (i) a lower release film located atop said lower tool; (ii) an upper release film positioned atop said lower release film and beneath said gas impervious layer; and, (iii) vacuum attachment means for attaching said upper and lower release films together such that said resin content control envelope is formed between said upper and lower release films; (c) an upper tool located between said gas impervious layer and said upper release film; and, (d) second conduit means positioned inside of said vacuum envelope and said resin content control envelope for providing a path for air and other gases between said dry preform and said first conduit means as said monolithic structure is created.",
    "39. Apparatus as claimed in claim 38 wherein said second conduit means comprises: at least one layer of inner breather tape positioned adjacent said dry preform within said resin content control envelope; at least one layer of vacuum port breather tape extending between the interior of said resin content control envelope and the exterior of said resin content control envelope; and, at least one layer of outer breather tape extending between said vacuum port breather tape and said first conduit means.",
    "40. Apparatus as claimed in claim 39 wherein said second conduit means comprises several layers of inner breather tape, several layers of vacuum port breather tape and several layers of outer breather tape.",
    "41. Apparatus as claimed in claim 40 wherein said inner breather tape layers surround the periphery of said dry preform, inside of said resin content control envelope.",
    "42. Apparatus as claimed in claim 39 wherein said upper tool is perforated and the lower surface of said upper tool is covered by a correspondingly perforated release film.",
    "43. Apparatus as claimed in claim 42 wherein said second conduit means comprises several layers of inner breather tape, several layers of vacuum port breather tape and several layers of outer breather tape.",
    "44. Apparatus as claimed in claim 43 wherein said inner breather tape surrounds the periphery of said dry preform, inside of said resin content control envelope.",
    "45. Apparatus for creating monolithic structures formed of layers of plies joined by a cured resin, said apparatus comprising: a vacuum envelope including first conduit means for connecting said vacuum envelope to a vacuum source; a resin content control envelope positioned within said vacuum envelope for enclosing a monolithic structure as it is being formed, said monolithic structure created from a dry preform formed of a plurality of plies and at least one layer of resin; and, second conduit means positioned inside of said vacuum envelope and said resin content control envelope for providing a path for air and other gases between said dry preform and said first conduit means as said monolithic structure is created, said second conduit means comprising: at least one layer of inner breather tape positioned adjacent said dry preform within said resin content control envelope; at least one layer of vacuum port breather tape extending between the interior of said resin content control envelope and the exterior of said resin content control envelope; and, at least one layer of outer breather tape extending between said vacuum port breather tape and said first conduit means.",
    "46. Apparatus as claimed in claim 45 wherein said resin content control envelope comprises: a lower release film; an upper release film positioned atop said lower release film; and, vacuum attachment means for attaching said upper and lower release films together such that said resin content control envelope is formed between said upper and lower release films.",
    "47. Apparatus as claimed in claim 45 wherein said second conduit means comprises several layers of inner breather tape, several layers of vacuum port breather tape and several layers of outer breather tape.",
    "48. Apparatus as claimed in claim 47 wherein said resin content control envelope comprises: a lower release film; an upper release film positioned atop said lower release film; and, vacuum attachment means for attaching said upper and lower release films together such that said resin content control envelope is formed between said upper and lower release films.",
    "49. Apparatus as claimed in claim 45 wherein said inner breather tape layers surround the periphery of said dry preform, inside of said resin content control envelope.",
    "50. Apparatus as claimed in claim 49 wherein said resin content control envelope comprises: a lower release film; an upper release film positioned atop said lower release film; and, vacuum attachment means for attaching said upper and lower release films together such that said resin content control envelope is formed between said upper and lower release films.",
    "51. Apparatus as claimed in claim 50 wherein said second conduit means comprises several layers of inner breather tape, several layers of vacuum port breather tape and several layers of outer breather tape.",
    "52. Apparatus as claimed in claim 51 wherein said resin content control envelope comprises: a lower release film; an upper release film positioned atop said lower release film; and, vacuum attachment means for attaching said upper and lower release films together such that said resin content control envelope is formed between said upper and lower release films."
  ],
  "description_excerpt": "This invention relates to fiber reinforced resin composites.\n\nIn recent years the use of high-strength-to-weight ratio fiber reinforced resin composites has continuously expanded, particularly in weight-sensitive, products, such as aircraft and space vehicles. Prior to the present invention, the fiber reinforced resin composites used in such products have usually been created by forming a layup, e.g., a stack, of layers or plies, the layers or plies being formed of unidirectional or multidirectional (e.g., woven) fabrics made of glass or graphite fibers impregnated with a resin. Such preimpregnated plies are commonly referred to as \"prepreg\" plies or simply prepreg. Normally the layup is positioned atop a forming tool, which, in its simpliest form, may comprise a flat plate. After the layup is prepared, heat and pressure are applied. The heat cures the resin and the pressure compresses the layup preventing air and other gases, including volatile gases, from forming porosity (bubbles) as the resin cures. Normally an autoclave is used to apply the necessary heat and pressure.\n\nWhile monolithic structures formed of fiber reinforced resin composites processed in the manner described above are satisfactory in some environments, they have certain disadvantages. For example, it has become desirable to provide cross-ply reinforcement in order to increase resistance to \"in-plane\" compression load failure, particularly after limited input damage. In-plane loads are those lying in the plane of the plies. Cross-ply reinforcement (sometimes referred to as Z-direction reinforcement) is created by cross-ply stitching a layup.",
  "cpc": [
    "B29B 15/105",
    "B29C 43/12",
    "B29C 70/342",
    "B29C 70/44",
    "B29C 70/547",
    "B29K 2105/108",
    "B29K 2105/256",
    "Y10T 428/24091",
    "Y10T 428/24099",
    "Y10T 428/24107",
    "Y10T 428/24149"
  ],
  "ipc": [
    "B29B 15/10",
    "B29C 70/34",
    "B29C 70/44",
    "B29C 70/54"
  ],
  "assignees": [
    "Boeing Co"
  ],
  "inventors": [
    "Leslie E. Letterman"
  ],
  "filing_date": "1984-11-29",
  "publication_date": "1986-11-11",
  "grant_date": "1986-11-11",
  "priority_date": "1984-11-29",
  "application_number": "US-67642784-A",
  "family_id": "24714467",
  "cited_by_count": 314,
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}