Dynamical model and control of plastics extruder processes

Alternative methods for determining plastics extruder process models, suitable for high level control, are examined and the importance of time-series techniques for feed forward control is demonstrated. The results of extrusion process dynamic model identification experiments, carried out on a single screw extruder used for processing polyethylene, are described. Some results of exploratory control strategy simulations are included. Control of plastics melt pressure and temperature at the die is suggested as an effective indirect means of controlling die flow rate in most industrial situations.