The vacuum extruder consists of an extrusion system, a transmission system, and a heating and cooling system. The heating and cooling device is a necessary condition for the extrusion process to be carried out. (1) Nowadays, electric heating is commonly used for the heating of vacuum extruders, which can be divided into resistance heating and induction heating. The heating plates are installed in the body, neck, and head of the machine. The heating device is composed of plastic inside an external heating cylinder, which is heated to reach the temperature required for the process operation. (2) The cooling device is set up to ensure that the plastic is within the temperature range required by the process. Specifically, it is to eliminate the excess heat generated by the shear friction of screw rotation, in order to avoid the difficulty of plastic decomposition, scorching, or shaping due to high temperature. Machine barrel cooling can be divided into two types: water cooling and air cooling. Generally, air cooling is more suitable for small and medium-sized extrusion machines, while water cooling or a combination of the two forms of cooling are more commonly used for large machines; The screw cooling mainly adopts central water cooling, with the aim of increasing the solid conveying rate of materials, stabilizing the glue output, and improving product quality; But the cooling at the hopper is to strengthen the conveying effect of solid materials, prevent plastic particles from sticking and blocking the material outlet due to temperature rise, and ensure the normal operation of the transmission part. The entire workflow of a vacuum extruder requires the coordination of the extrusion system, transmission system, and heating and cooling system to complete, and the important workflow of product forming requires the heating and cooling system to complete. Therefore, the heating and cooling device is an important component of a vacuum extruder.
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