Method of injection molding a plastic plate

摘要

A method of forming a plastic sealing plate for a compressor valve. A center gated mold is employed in conjunction with a heated barrel which encloses a reciprocating screw for feeding plastic through an injector into the mold. Polyetheretherketone polymer pellets are heated to about 150 DEG C. to remove moisture after which they are fed into and through the heated barrel, the heated barrel being elevated to a temperature in the range of 350 DEG -380 DEG C. for melting the pellets. The mold is heated to a temperature in the range of 150 DEG -180 DEG C. The melted polymer is then injected into the mold by the reciprocating screw to obtain proper mixing and pressurizing, after which the mold is heated to a temperature of about 300 DEG C. to anneal the plastic in the mold and to expand the polymer to fill the entire mold and relieve stress in the material.