Injection unit of an injection molding machine and control method thereof

摘要

A screw is installed in a heating barrel. The rear end of the screw is supported by an intermediate plate via a bearing. The servomotor for charging is connected to a near the rear end of the screw. To the back surface of the intermediate plate, a direct current linear motor for injection is connected via a load cell. The load cell detects the axial direction load applied to the rear end of the screw by the pressure of the molten resin in the heating barrel during charging, and also detects the axial direction load applied to the rear end of the screw for moving the screw forward during injection. The current to be supplied to the DC linear motor is controlled in a feedback manner based on the detected axial direction load, thereby bringing the pressure of the molten resin in the heating barrel closer to a predetermined pattern.