Dalian extrusion molding is one of the more common plastic molding methods at present. It is suitable for all thermoplastics and some thermosetting plastics. It can form all kinds of plastic pipes, bars, plates, wires and cables and special-shaped section profiles. It can also be used for coloring, feeding and blending of plastics.

The quality of extruded profile depends on the extrusion die, which is mainly composed of machine head and setting device. The rationality of its structural design is the decisive factor to ensure the forming quality of plastic parts. Firstly, granular or powdery plastic is added into the hopper. Under the action of the rotating screw of the extruder, the heated plastic is transported forward along the spiral groove of the screw. In this process, the plastic continuously receives external heating and shear friction heat between the screw and the material, between the material and the material and between the material and the barrel, and gradually melts into a viscous flow state. Then, under the action of the extrusion system, the plastic melt passes through the extrusion die (head) with a certain shape and a series of auxiliary devices (setting, cooling, traction, cutting, etc.) 。

When manufacturing thin-walled rubber products, in order to prevent air and water leakage of the products, the rubber material shall not contain impurities. Generally, the rubber material shall be filtered by extruder before adding vulcanizing agent, that is, one or more layers of filter screens shall be placed at the head to filter the impurities in the plasticized materials. One extruder can be used to extrude a rubber material through a flat die; Two kinds of rubber (crown material and sidewall material) can also be co extruded by two extruders to form an integral tread in the co extruder head. For layered extrusion, two extruders are used to extrude the two kinds of rubber into tire crown and sidewall respectively, and then thermal bonding is carried out on the conveyor belt, which is rolled into a whole by multi disc flexible roller. Inner tube extrusion is similar to tube extrusion. After the tube is extruded, it is cut off and then formed.