Injection molding machine screw barrel is a long time i […]
Injection molding machine screw barrel is a long time in the high pressure, high temperature, high mechanical torque and high friction environment to work. The first few factors are required process conditions, but the friction caused by the loss is inevitable. General screw surface nitriding have been carried out to improve the surface hardness, that is, to improve anti-wear ability. However, if you neglect the cause of wear and tear, try not to minimize wear and tear, will inevitably greatly reduce the working life of the screw.
The following two points to introduce the cause of the screw wear and reduce wear
1, Each plastic raw material, there is an ideal plasticizing processing temperature range, it should control the barrel processing temperature, so close to this temperature range. Granular plastic from the hopper into the barrel, the first will reach the feeding section, the feeding section is bound to appear dry friction, when these plastics are not enough heat, uneven melting, it is likely to cause the barrel wall and screw surface wear increased; the same, In the compression section and the homogenization section, if the molten state of the plastic is not uniform, the wear will also be increased.
2, speed should be properly adjusted. Because part of the plastic with toughening agent, such as fiberglass, minerals or other fillers. The friction of these materials on metallic materials is often much greater than that of molten plastic. In the plastic injection of these plastics, if the use of high speed, then increase the shear on the plastic at the same time, will also make fortification correspondingly produce more torn fibers, torn fibers have sharp ends, so that wear The power is greatly increased. Inorganic minerals in high-speed sliding metal surface, the scraping effect is not small. Therefore, the speed should not be adjusted too high.