EFFECT OF DESIGN AND OPERATING CONDITIONS ON MELTING IN PLASTICATING EXTRUDERS

A previously proposed but further modified theoretical model for melting in plasticating extruders, in the form of a computer program, which predicts the amount of unmelted polymer at any point in the extruder, was used to simulate the effect of geometrical and operating variables on the melting performance of the extruder. The results indicate in increasing screw length required to complete melting with increasing throughput and a decreasing length of melting with increasing frequency of screw rotation. They further indicate the existence of an optimum barrel temperature for a maximum rate of melting, an optimum number of threads for a maximum melting rate, and a significant decrease in the rate of melting with increasing flight clearance. The effect of other geometrical variables and of operating conditions on the rate of melting and power consumption are also discussed. Copyright © 1969 Society of Plastics Engineers, Inc.