Single diaphragm forming of drapeable thermoplastic impregnated composite materials

  • US 5,037,599 A
  • Filed: 06/26/1989
  • Issued: 08/06/1991
  • Est. Priority Date: 06/26/1989
  • Status: Expired due to Term
First Claim
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1. A process for repetitive thermoforming for the preparation of non-planar fiber reinforced thermoplastic composites, comprising:

  • a. selecting a tool having surface contours identical to one face of the composite desired to be prepared;

    b. laying upon the tool surface one or more layers of a drapeable prepreg;

    c. employing not more than one deformable, planar diaphragm located on the side of the drapeable prepreg laid up in step (b) most remote from the tool surface;

    d. establishing a pressure differential between the side of the diaphragm most remote from the tool surface and the tool or surface of the prepreg adjacent to the tool and heating the prepreg laid up in step (b) to a processing temperature under conditions such as to fuse and consolidate thermoplastic located within the prepreg and form an integral thermoplastic fiber reinforced composite part;

    such that the planar diaphragm has been deformed to coincide with the surface of the composite part most remote from the tool;

    e. removing said deformed diaphragm and said integral composite part from the tool;

    f. selecting the same tool utilized in step (a) for a repetition of the thermoforming process and then;

    g. repeating step (b);

    h. employing as a diaphragm the non-planar, deformed diaphragm formed in step (d) on the side of the prepreg laid up in step (g) most remote from the tool surface;

    i. establishing a pressure differential between the side of the diaphragm most remote from the tool surface and the tool or surface of the prepreg adjacent to the tool and heating the prepreg laid up in step (g) under conditions such as to fuse and consolidate thermoplastic located within the prepreg to form an integral thermoplastic fiber reinforced composite part;

    j. removing said non-planar deformed diaphragm and said integral composite part formed in step (i) from the tool; and

    k. optionally repeating steps (f)-(j).

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