1. Each plastic has an ideal plasticizing processing temperature range, and the barrel processing temperature should be controlled to bring it close to this temperature range. When the granular plastic enters the barrel from the hopper, it will first reach the feeding section, and dry friction will inevitably appear in the feeding section. When these plastics are insufficiently heated and melted unevenly, it is easy to cause the inner wall of the cylinder and the surface of the screw to wear more. Similarly, in the compression section and the homogenization section, if the molten state of the plastic is disordered, the wear will increase. 2, the speed should be adjusted properly. Some plastics are supplemented with reinforcing agents such as fiberglass, minerals or other fillers. These materials tend to have a much greater frictional force on metallic materials than molten plastics. When molding these plastics, if they are made at a high rotational speed, the shearing force on the plastic will be increased, and the reinforcement will also produce more shredded fibers correspondingly. The shredded fibers contain sharp ends and wear. The power is increasing. When the inorganic minerals slide at high speed on the metal surface, the scraping effect is not small. Therefore, the speed should not be adjusted too high.
3. The screw rotates in the barrel, and the friction between the material and the two causes the working surface of the screw and the barrel to wear gradually: the diameter of the screw is gradually reduced, and the diameter of the inner hole of the barrel is gradually increased. Thus, the matching diameter gap between the screw and the barrel increases little with the gradual wear of the two. However, since the resistance of the front head and the splitter plate of the barrel is not changed, this increases the leakage flow when the extruded material advances, that is, the amount of material flowing from the diameter gap to the feed direction increases. As a result, the production of plastic machinery has decreased. This phenomenon causes the residence time of the material in the barrel to increase, causing the material to decompose. In the case of polyvinyl chloride, the hydrogen chloride gas generated by the decomposition enhances the corrosion of the screw and the barrel.
4. If there are fillers such as calcium carbonate and glass fiber in the material, it can accelerate the wear of the screw and the barrel.
5. Since the material is not plasticized evenly, or metal foreign matter is mixed into the material, the torque of the screw is suddenly increased. This torque exceeds the strength limit of the screw, and the screw is broken. This is an unconventional accident damage.