The screw of the injection molding machine works under […]
The screw of the injection molding machine works under high temperature, high pressure, high mechanical torque and high friction environment for a long time. The first few factors are required by the process conditions, and the loss caused by friction is inevitable. Generally, the screw has been subjected to surface nitriding treatment to improve the surface hardness, that is, to improve the anti-wear ability. However, if the cause of wear is neglected, and the wear is not reduced as much as possible, the working life of the screw will be greatly reduced.
The following will focus on the causes of screw wear and methods to reduce wear:
1. Each plastic has an ideal plasticizing processing temperature range, the barrel processing temperature should be controlled to make it close to this temperature range. The granular plastic enters the feeding barrel from the hopper, and will first reach the feeding section. Dry friction will inevitably occur in the feeding section. When these plastics are insufficiently heated and unevenly melted, it is easy to cause increased wear on the inner wall of the barrel and the screw surface. Similarly, in the compression section and the homogenization section, if the molten state of the plastic is disordered, it will also cause increased wear.
2. For certain types of plastics, under high temperature and pressure, moisture may become a catalyst that promotes the cracking of plastics, producing harmful impurities that can attack the metal surface. Therefore, the drying work before plastic injection not only has a direct relationship with the production volume, but also affects the working life of the screw.