Injection molding machine using a pulsating pressing force

摘要

A locally pressing type injection molding machine which performs various working operations on a molded product during an injection molding cycle is designed so that it can perform various working operation on a molded product after the injection step. To achieve this, a pressing pin is provided to extend in such a manner that it passes through at least part of either the fixed mold or the movable mold. A distal end of the pressing pin is provided in such a manner that it can advance into or retract from a cavity. A pressing cylinder is disposed behind the pressing pin to vibrate the pressing pin when a hydraulic pressure supply means supplies a pulsating hydraulic pressure to the pressing cylinder. A pulsating pressing force is applied to a resin which fills the cavity to work the molded product in a desired form. Therefore, a highly accurate worked surface can be obtained.