Effect of speed sinusoidal pulsating enhancement on the mixing property of plastic machinery

Abstract Numerous vibration-assisted methods have been adopted to solve problems in polymer processing, but the introduction of vibration fields is typically done on small extruders or injectors in school laboratories and industrial research rooms, which profoundly limits the application of vibration technology. The purpose of this study is to put forward a simple vibration excitation method for all scale extruders or injection molding machines. To recover the mixing performance of that excitation method, a numerical investigation was carried out using the CFD software ANSYS POLYFLOW 19.2, and the analysis and comparison were made between the mixing performance of a simplified screw element with and without a sinusoidal pulsating speed field. The results showed that not all dynamic states with the superimposed excitation field have better mixing performance than the steady state without any pulsating field. Nevertheless, the introduction of a pulsating speed field under certain parameters setting can indeed enhance the stretching rate, reduce the separation scale, increase the mixing efficiency, and lower the screw force. These findings are of great importance and provide valuable references for the development and application of vibration-assisted molding technology in plastics machinery.