CONTROL OF THE SHEAR STRAIN IN THE HOMOGENIZATION ZONE OF THE DISK EXTRUDER

Abstract

A simple method for determining the quality of a polymer melt is very important in production. A method that provides simplicity and quick use, making it valuable for optimizing extrusion processes.

This work describes how the mixing effect can be improved by changing the velocity fields and thereby changing the shear strain values. The shear strain has been calculated for all four channels of the homogenization zone of a disk extruder. It was found that changing the disk rotation frequency allows changing mean value of the channel shear strain rate from 3324 to 4966 with constant performance for the entire homogenization zone. The impact of the different channels on the mixing effect was evaluated, with the first, second, third, and fourth channels contributing 21%, 57%, 15%, and 7% respectively to the overall homogenization zone's effectiveness of mixing. Additionally, it was found that the second channel experiences the highest shear strain values. In the case of the third channel, although the shear rate values are relatively high, the short residence time of the melt element results in comparatively smaller shear strain values. The average shear strain values remain constant for a given disk speed. It is indicated that it is possible to assess the quality of mixing by the amount of energy supplied, which simplifies the process of determining the quality of the melt, as well as its regulation.