Control Strategy of Screw Motion During Plasticizing Phase for All-Electric Injection Molding Machine

Abstract

This work studies a control strategy of screw motion to improve the plasticizing precision for an all-electric injection molding machine (AIMM) based on a biaxial simultaneous motion system. In the standard plasticizing process, a screw retraction before or after the metering phase is proposed to link up with the traditional metering process for reducing the residual pressure at the end of holding and metering, respectively. The modified incomplete plasticizing process is then applied to prevent the potential over-travel of the screw. The incomplete plasticizing process uses a control strategy to obtain a fixed start point for the screw at injection in each cycle. Experimental results showed that both the standard and incomplete plasticizing process improve the visual quality and molded precision of parts.