Extrusion is the process of pressing heated plastic material into the extruder barrel through screw pressure, and then shaping the plastic material through the extrusion hole of the extrusion head. The characteristic of this process is that it can produce long and uniformly shaped plastic products, such as electrical conduits, door and window frames, and daily use pipelines. The advantages of extrusion technology are simple operation and the ability to produce elongated plastic products, but the disadvantages are the problem of screw thread and surface roughness.