Preliminary compressed injection molding manner

摘要

PURPOSE:To provide a prepressurizing injection molding method preventing an occurrence of phenomena, such as a silver streak and a surface roughening, on a surface of a molded article. CONSTITUTION:Before or after the contact of parting faces of injection molds used for molding a resin, a compressed air or inactive gas is blown into a space 9 formed by a movable mold 2 and a stationary mold 1. An internal pressure is regulated by exciting a proportional solenoid pressure regulating valve 17. A prepressurizing force is kept at 1-5kgf/cm2 G.