When extruding rubber compounds with a rubber screw barrel, it is mainly the heating of the barrel and the screw, which, in addition to the number of revolutions, also significantly affects the product quality and output. With sufficient thermal and material uniformity, the throughput rate at low material temperatures can be improved by optimizing heating conditions.
Regarding the throughput behavior as a function of heating, it is necessary to consider the absolute throughput or specific throughput as a function of rotational speed on the one hand, and throughput as a function of melt temperature on the other hand, respectively. To avoid thermal damage or even vulcanization of the rubber compound during extrusion, the maximum allowable temperature of the material must not be exceeded.
To accurately determine the effect of heating on throughput behavior during extrusion, an experimental study was carried out on two rubber extruders of different sizes. In addition, numerical flow simulations of non-isothermal shear-thinning melt flow were performed taking into account dissipative heating in the screw channel.