TEMPERATURE-MEASUREMENTS OF POLYMER MELTS IN THE HEATING BARREL DURING INJECTION-MOLDING .3. EFFECTS OF SCREW GEOMETRY

We have developed a new method to measure the true temperature of the polymer melt and its three‐dimensional distribution of a shot stored in the reservoir during injection. By means of this method, it is demonstrated that the temperature distribution of the polymer melt stored in the reservoir is strongly dependent on the setup molding conditions, the polymer investigated, and the geometry of the screw used. Further, it is noted qualitatively that there are two major effects of screw geometry on the temperature distribution of polymer melts. One, which governs strongly the temperature in the high temperature zone, is shear heat generated within the polymer itself in the metering zone of the screw during the transporting process. The second is the ability to preheat and plasticate the polymer in the compression zone, which is indispensable for uniform plastication. Copyright © 1990 Society of Plastics Engineers