Method of fabricating fiber reinforced composite articles by resin transfer molding

Claim 1

In a method of fabricating a fiber reinforced composite article including stacking a plurality of dry fabric plies, shaping the plies into the desired shape, and stabilizing said plies to form a dry fiber preform, placing the stabilized dry fiber preform into a resin transfer molding means, injecting a thermosetting resin into the resin transfer molding means under pressure to impregnate said stabilized fiber preform with the thermosetting resin, and heating said stabilized fiber preform and thermosetting resin to cure the thermosetting resin and form the fiber reinforced article, the improvement in forming the dry fiber preform comprising: stabilizing the plies by disposing about 5 grams to about 20 grams of polymeric binder per square meter fabric ply surface between each pair of adjacent dry fabric plies, laying up the fabric plies on a shaped perforated mandrel, applying compaction pressure against the fabric plies by a tool having a body fabricated from a low heat conductive material, wherein the tool is shaped to conform to the mandrel and, while applying said compaction pressure, first passing hot air at a temperature of approximately 250° F. to 400° F. through the tool at air pressure sufficient to penetrate all of the fabric plies and subsequently passing relatively cool air at room temperature or below through the tool at air pressure sufficient to penetrate the fabric plies, whereby the fabric plies form a high density stabilized dry fiber preform.