Visualization Analysis of Plastication Process in Vent-type Heating Cylinder

Abstract

The plastication process in the vent-type heating cylinder of the injection molding machine was visually analyzed. It was clarified that voids are formed in the molten resin in the channel of the second screw zone near the vent port. In the continuous plasticization process, the void space expanded toward the nozzle side as the screw rotation speed increased, due to an imbalance of the resin transport rates between the first and second screw zones. In the reciprocating plastication process, the material feed rate at the hopper inlet for controlling venting-up phenomena increased more than the increase in the screw rotation speed, due to the increase in the resin transport rate in the second screw zone.