Polish version

Login form

register


Print

B. Broel-Plater, J. W. Sikora

Extrusion process as an automatic control object

Polimery 2004, No 2, 114


Summary

On the example of technological line for covering thermoplastic insulation on an electric wire, the tasks that an automatic system to control such a line must fulfill are presented. On this basis two sub-systems are distinguished. One of them is designed to control the properties of the processed plastic via influencing the processes taking place within the plastifying system and extruder head. The other one is designed to control the product displacement along the extruder line, i.e. the processes taking place outside the extruder. In the control systems currently used for extrusion the above mentioned systems operate independently. The quality of an extrudate can be improved if both systems are cooperating in that the temperature set-point values at extruder zones are dependent on plastic flow intensity correlated with the rate of extrusion. Creating such a system requires a computer-based control. The solution preceding such a system creation can be the use of specialized programmed controllers. The quality of extrudate can also be improved by the algorithms based on artificial intelligence using, first of all fuzzy logic, to control the extruder line. Fuzzy logic based control algorithms can be applied to both multidimensional control of properties of the processed plastic and complex control of product displacement along the extruder line. In order to illustrate the fuzzy logic based control algorithms use, the results of computer simulated product displacement along the extruder line are depicted. As a result of using fuzzy logic control, a substantial improvement of the quality of product displacement process has been achieved which manifests itself in lowering the plastic tensile stress and limitation of tightening compensators shifting and, at the same time, increase in the line rate of starting and stopping.


Keywords: extrusion, automatic control, plastifying system, extruder head, extrudate displacement outside the extruder


B. Broel-Plater, J. W. Sikora

Extrusion process as an automatic control object