In the extrusion production of plastics, there may be various impurities and foreign substances in the raw materials as well as fine crystalline particles with incomplete plasticization, especially in the recycling process of recycled plastics, there are paper scraps, aluminum foil, sand, iron scraps, copper wire, wood scraps, defoamer and other impurities, the existence of these impurities without the installation of a mesh changer. Impurity filtration will result in the decline of product qual