Modeling of a screw extruder 3D printer using pellets or crushed polymer waste as the raw material

Abstract

In this article, the process of moving polymer material in the screw extruder of a 3D printer, which uses granules or crushed polymer waste as raw materials, is chosen as the object of mathematical modeling. It is noted that the modeling of screw extruders is a highly relevant task, as it is an essential tool for optimizing production processes in the polymer industry and other industries where they are used. It allows you to study and optimize the material cylinder's processes thoroughly. It is noted that the modeling of screw extruders for 3D printers, which use granules or shredded plastic waste, is a critical factor in supporting innovation, increasing production efficiency, improving product quality, and developing new technological solutions in various industries. It was noted that during the movement of the material along the channel of the extruder screw, several of its states continuously changed from a solid at the entrance of the channel to a viscous liquid at the exit. In the feed zone, the polymer is solid and moves along the material cylinder due to friction. A physical model was used in the simulation, in which compacted polymer particles do not move relative to each other during movement through the channel. This is because the internal friction forces in the polymer greatly outweigh the friction of the polymer on the steel, and the particles move as a single elastic compressible medium due to the balance of dry friction between the cylinder wall and the screw. The geometrical parameters of the extruder in the feed zone are shown. A diagram of the expanded extruder channel for calculating productivity is given. A diagram of the movement of material in it was drawn up to determine the productivity of the extruder feed zone. A mathematical model of productivity was obtained depending on the diameter of the screw, the frequency of rotation, the depth of the screw channel, and the angle of elevation of the screw line of the screw cutting. The pressure in the extruder channel was calculated. A scheme for calculating the forces acting on the material in the feeding zone is given. A formula was obtained for determining the pressure in the material loading zone from the hopper, which connects the characteristics of the polymer material and the geometric parameters of the loading hopper. Keywords: 3D printer, screw extruder, modeling; polymer material; loading area; bunker; productivity; pressure.