Fundamentals of Operations in Plastics Processing Plants as a Result of the Investigation of Process Control.

This is a comprehensive report on the research project on ″process control″ conducted at the West German Plastics Processing Institute. General considerations of process control are followed by a presentation of experimental results obtained with the control of process variables in injection molding and extrusion. In injection molding the following subjects are considered - setting-up the follow-up pressure, determination of cooling time, acceleration of the running-in cycle for new molds and the re-use of old molds. The process control of extrusion is discussed under headings - general concept (extrusion blow molding, sheet extrusion), findings on the thermal influences, influence of temperature fluctuations on the geometry of the extruded profile, accelerated start-up of lines using large dies, calculation of the temperature and its distribution in sections during extrusion and cooling, findings useful for shaping and injection blow molding, findings useful for mechanical engineering and instrumentation of conventional equipment.