The molds used in the production of plastic automated extruders have different combinations of core and sleeve according to different product and process requirements. Extrusion molding requires high accuracy in mold matching. If the performance of the extruded sheet is poor, it is due to the difference in the matching angle between the mold core and the mold sleeve that determines the size of the pressure, which affects the quality of the plastic layer and the extrusion yield; The dimensions of the mold core and sleeve also directly determine the geometric shape and surface quality of the extruded product. The aperture of the molded part of the sleeve must consider comprehensive factors such as "expansion" after pressure relief and shrinkage after cooling.