Measurement of screw torque profiles along axial direction in injection molding process I - development of measurement method

摘要

The shearing operation is the most important factor in the screw plastication process. In order to clarify the shearing operation along the screw axis, we developed an experimental screw and measurement system, for measuring the torque profiles in the axial direction of the screw. The experimental screw was divided into several segments along the axial length, and each segment had strain gauges attached to the inner-hole surface. Using this equipment, the torque profiles and torque deviation profiles in the axial direction of the screw were measured during the plastication of polypropylene. The validity of this method was also confirmed. The observed results corresponded exactly to the polymer melting behavior observed by dynamic visualization using a visual heating cylinder. In particular, the effects of the melting behavior, such as the variation of the solid-bed ratio, the break-up phenomena, and the change of the relative position between the screw and the area where melting starts on the transition of the screw torque profiles during the reciprocating plastication process were investigated. Further studies such as quantitative analyses of the plastication phenomena using different screw configurations by combining with the visualization technique are planned.