How to reduce the wear of bimetal screw?
The bimetal screw works under high temperature, high pressure and high friction conditions. These factors cause the loss of the bimetallic screw although it is inevitable, but it is also a necessary condition for the production process. Generally, the screw has undergone surface nitriding treatment to improve the surface hardness, that is, to improve the wear resistance. However, if the causes of wear are ignored and the wear is not minimized, the working life of the screw will be greatly reduced.
1. Each plastic material has an ideal plasticizing temperature range, so the barrel processing temperature should be controlled to make it close to this temperature range. Granular plastic enters the barrel from the hopper and first reaches the feeding section. Dry friction will inevitably occur in the feeding section. When these plastics are not heated enough and melted unevenly, it is easy to cause the inner wall of the barrel and the surface of the screw to increase wear; In the compression section and the homogenization section, if the molten state of the plastic is disordered and uneven, it will also cause increased wear.
2, the speed should be adjusted properly. Because some plastics are added with strengthening agents, such as glass fiber, minerals or other fillers. The friction of these substances on metal materials is often much greater than that of molten plastics. When injecting these plastics, if a high speed is used, while increasing the shearing force to the plastic, it will also cause the reinforcement to produce more shredded fibers. The shredded fibers contain sharp ends, causing wear The force is greatly increased. When inorganic minerals slide at high speed on the metal surface, their scraping effect is not small. So the speed should not be adjusted too high.