AN ELECTROSTATIC POWDER SPRAY PROCESS FOR MANUFACTURING THERMOPLASTICCOMPOSITES

Manufacture of thermoplastic composites is expensive because of the di fficulty of impregnating the resin into the fibers. Powder processing shows great promise as an impregnation technique for cost-effective ma nufacturing. This paper discusses an electrostatic powder spray impreg nation technique that uses glass fibers. A geodesic fiber spreader is used to spread the fibers locally in the region of maximum powder depo sition. A negative corona electrostatic spray gun is employed to charg e and direct the powder for coating both sides of the spread fiber tow . The process has been used to impregnate glass fibers with poly(aryl ether ketone ketone) powder. The effect of the powder mass flow, coron a voltage, and fiber tow velocity on powder deposition has been invest igated. Particle image velocimetry is utilized to determine particle v elocities. Compression molded panels have been produced and tested in three point bending.