When the machine presents a fault situation, we need to find out the cause of it, so as to solve it. What are the reasons for the wear of the screw of the pipe extrusion machine?
1. Each kind of plastic has an ideal plasticizing processing temperature range. The processing temperature of the barrel should be controlled to make it close to this temperature range. When granular plastics enter the barrel from the hopper, they will first reach the feeding section, and dry friction will inevitably occur in the feeding section. When these plastics are not heated enough and melt unevenly, it is easy to cause increased wear on the inner wall of the barrel and the surface of the screw. Similarly, in the compression section and homogenization section, if the melting state of the plastic is disordered and uneven, it will also cause accelerated wear.
2. The screw rotates in the barrel, and the friction between the material and the two makes the working surface of the screw and the barrel wear gradually: the screw diameter is gradually reduced, and the inner hole diameter of the barrel is gradually increased. In this way, the fit diameter gap between the screw and the barrel increases gradually with the gradual wear of the two. However, since the resistance of the head and distributor plate in front of the barrel has not changed, this increases the leakage flow of the extruded material when it moves forward, that is, the flow of the material from the diameter gap to the feeding direction increases.
3. The speed should be adjusted properly. Because some plastics are fortified, such as glass fiber, minerals or other fillers. The friction force of these substances on metal materials is often much greater than that of molten plastics. When these plastics are injected with high rotational speed, the shear force on the plastics will be increased, and the reinforcement will correspondingly produce more torn fibers. The torn fibers contain sharp ends, which greatly increases the wear force.
