Measuring Performance of an Eight-Inch Cable Sheathing Extruder

摘要

Experimental studies on extrusion of polyethylene were carried out on an 8-inch diameter 20/1 length cable jacketing extruder. Objectives included the study of temperature and pressure action, performance evaluation of a new compression-relief type screw, collection of operating data for building a theoretical model of the process, and to provide equipment for a separate study of the effect of operating variables on stress-cracking resistance of product. The extruder was instrumented with 7 pressure transducers, 6 thermocouples in the screw, 23 thermocouples for plastic temperature mounted from the screw, and several thermocouples in the barrel and head. Fifteen equilibrium experiments were performed at various conditions of barrel temperature, screw speed, and die constriction. Strip chart records were made of all instruments, and moving pictures were made of temperature and pressure profiles. Results confirmed that temperature action in the 8-inch machine was similar to that previously reported for a 2.5-inch extruder. Utility of the compression-relief type screw for this application was established. A theoretical model for the process has been fitted to these experiments. (Author)