Extrusion Characteristics And Modeling Of Polyolefine In Deformation Enhanced Vibratory Shear Field

Extrusion is one of the important polymer processing and molding methods, this method is widely used in the production of films, pipes, plates, sheets and other products. Screw extruder is the main equipment of extrusion molding. In the traditional screw extruder, the movement of the screw is only circumferential rotation motion, so that the production of materials is under the action of shear stress field. By studying the melt rheological behavior under the vibration force field, scholars found that the melt viscosity and the extrusion pressure is reduced, the volume flow rate increases. Most of the melt vibration equipment is installed in the head part, formation of the vibration field is partial, and it does not make full use of the vibration technology in the polymer processing industry. The design of dynamic mechanical drive type extruder for this problem implements the introduction of the technique of vibration to the whole process of polymer processing, through vibration system making the screw axial rotation and axial vibration work together.Production,power are the important indicators to measure a extruder performance. This paper discusses the working principle of vibration system, analyses the motion process of the screw axial movement. At the same time, this paper establishes the corresponding physical model and mathematical model, theoretically studies the extrusion characteristics under the action of vibration shear deformation strengthening, and the experimental measurement is based on low density polyethylene as raw materials, analyses the screw rotation speed, vibration amplitude, vibration frequency and other effects on extrusion output and power. The research results show that: Screw transmission through vibration system has realized the axial vibration, vibration amplitude is related to the location of the joint bearing, vibration frequency is related to vibration motor speed; mathematical model analysis shows that, under the effect of vibration force field, the extrusion pressure is lower than the steady extrusion pressure, at the same time, extrusion power also has a certain degree of decline. With low density polyethylene as the experimental material, the extrusion pressure increases with the engine speed increases. At the same speed, the extrusion pressure decreased with increasing vibration amplitude or frequency. The vibration intensity is higher, the extrusion pressure decreased more obviously, the changing rule of the extrusion power and output is similar to the extrusion pressure. Power increases with extrusion pressure increases.