Generally, the screw rods have been nitridized to impro […]
Generally, the screw rods have been nitridized to improve the surface hardness, that is, to improve the wear resistance. But if it is neglected, the screw of the injection molding machine is operated under high temperature, high pressure, high mechanical torque and high friction environment for a long time. The process conditions of the first few factors are required, and the wear caused by friction is inevitable. The cause of wear, not trying to reduce wear as much as possible, will inevitably reduce the life of the screw. In order to ensure the safe and stable production of the injection molding machine screw and prolong its service life, the maintenance work of the injection molding machine screw must be strengthened. The basic contents are as follows:
(1) Each 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 the granular plastic enters the barrel from the hopper, it will first reach the feeding section and then the feeding section Dry friction will inevitably occur. 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 surface of the screw. Similarly, in the compression section and homogenization section, if the molten state of the plastic is uneven , Will also cause increased wear.
(2) The speed should be adjusted properly. Because some plastics are filled with reinforcing agents, such as glass fiber, minerals or other fillers. These materials treat the frictional force of metal materials is often much greater than that of molten plastics. In the injection molding of these plastics, if the high speed is used, the shear force on the plastic will be increased, and the reinforcement will accordingly produce more shredded fibers. The shredded fibers contain sharp ends. The wear force is greatly increased. When the electrodeless mineral glides on the metal surface at high speed, its scraping effect is also quite a lot. Therefore, the speed should not be adjusted too high.