The Analysis of the Present and New Solutions of the Adjustable Grooved Feed Section of the Extruder

Abstract

The paper will present the state of the art of the existent constructional solutions of the adjustable grooved feed section of a single screw extruder. This section is characterized by the fact that during the extrusion process it is possible to change the geometrical elements of the grooves without the need to stop the operation of the extruder and conduct the time-consuming exchange of the grooved sleeve. Next, different new conceptions will be presented. Selected solutions will be presented as 3D virtual models. For this reason software Catia v5 will be used. The developed models are fully functional. They were tested for their regularity and collision occurrence. Also, virtual prototypes were created to determine the risk of any irregularities during movement. Selected models underwent numerical calculations. The range of the conducted numerical analyses included calculations concerning the estimation of the strength of construction elements exposed to the pressure caused by the transfer of polymer in the form of pellets as well as thermal calculations enabling to receive the temperature distribution as a result of friction of the material against the inner walls of the grooved section. Also, calculations for particular models were made, in which a geometrical element was changed, e.g. the height of grooves. The results included the output, the average melt temperature at die exit, the pressure, the mechanical power consumption, the length required for melting, the mixing degree (quantified by WATS, a measure of the average strain suffered by all the particles inside the extruder) and the viscous dissipation (calculated as the ratio between the maximum and the barrel temperatures).