DOI: 10.36347/sjet.2017.v05i11.010

Pages: 668-674

The extrusion of PVC polimers with a single screw has been studied. Experimentally, the pressures and temperatures were measured at the end of each stage, for different processing conditions (screw speed, die geometry etc.). Screw pulling experiments have allowed to observe the partially filling of the screw sections. The evolutions of the pressure and the temperature all along the screw, as well as the filling length of the screw are then obtained. The theoretical results are in good agreement with the experimental measurements. When characteristics of the system are examined, it becomes clear that a commonly used proportional plus integral plus derivative PID controller cannot meet such performance specifications for this kind of system. In order to achieve the required performance, a control strategy that parameter PID is formulated. This control strategy proves to be very effective in achieving the referred specifications.