Method for producing plastic composite molded parts

Plastic composite gears and bearings with excellent friction and wear properties and further, plastic composite molded parts with excellent dimensional accuracy, can be presented at a low cost without adding large quantities of solid lubricant and glass fibers, etc., by adding a crystalline nucleus to crystalline polymers, such as polyacetal, polyamide, polyphenylene sulfide, etc., molding while applying vibrational energy, heat-treating the molded part after molding at a temperature that is the glass transition point of the crystalline polymer or higher and the melting point of the crystalline polymer or lower, heat treating the molded part after molding in the presence of a natural mineral, or by irradiating the molded part after molding with far infrared rays or infrared rays in order to reduce spherulite size of the crystalline polymer in the molded part and increase the degree of polymerization and thereby control crystal morphology and reduce the coefficient of friction and specific wear rate, and the molded parts have excellent recyclability.