Instabilities in the extrusion of polymers due to spurt

Abstract

The manufacturing of plastic products from polymeric melts is one of the main processes in chemical industry. Examples are the blowing of thin films, the extrusion of fibres or the injection moulding of disc-shaped products. Sometimes peculiar, and often unpleasant, effects occur during these manufacturing processes. Generally, these effects show up when the rate of production is raised. Hence, it is of capital importance for the efficiency of the process to know when these effects appear and how they can be avoided. For this, it is necessary to discover what causes this effect and, therefore, to find a theoretical explanation for it is of great practical value in polymer processing.