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Injection screw is a long time in high temperature, high pressure, high mechanical torque and high friction environment to work, the process conditions need the first few factors, and the loss caused by friction is inevitable. Usually, the screw is treated with surface nitriding to improve the surface hardness, that is, to improve the wear resistance. But if you ignore the causes of wear, do not try to reduce the wear as far as possible, will greatly reduce the service life of the screw, the following description causes of screw wear and reduce wear methods.

1. Each type of plastic has an ideal plasticizing processing temperature range. The processing temperature of the cylinder should be controlled to make it close to this temperature range. The granular plastic enters the barrel from the hopper. It will first reach the charging section, where dry friction is bound to occur. When these plastics are not heated enough, melting is uneven, it is easy to cause the inner wall of the cylinder and screw surface wear increases, similarly, in the compression section and homogenization section, if the melting state of plastic is uneven disorder, will also cause wear increase.

2, the speed should be adjusted properly. Due to the addition of some plastic agents, such as glass fiber, minerals or other fillers, the friction of these substances on the metal material is often much larger than that of molten plastic. In the injection of these plastics, if the high speed into, in improving the shear force of plastic at the same time, will also strengthen the corresponding production of more shredded fibers, shredded fibers contain sharp ends, so that the wear force is greatly increased, inorganic minerals in the metal surface high-speed sliding, its scraping effect is not small, so the speed should not be too high.

3, to check the debris in plastic. Generally speaking, the fresh plastic originally purchased does not have any debris, but after transportation, weighing, drying, mixing color, especially adding recycled material, there may be debris mixed with, such as metal scraps, as large as heating ring nuts and paper clips, and even strings of warehouse keys, mixed into the feeding cylinder has happened. This damage to the screw is self-evident (the cylinder will of course be damaged at the same time), so it must be installed magnet rack, strict feeding management and monitoring.

4. The moisture contained in the plastic has a certain effect on the wear of the screw surface. If the plastic in injection molding before the water is not completely eliminated, the residual water into the screw compression section, before the formation of melting mixed in molten plastic with high temperature pressure “steam particles”. With the advance of the injection process of the screw, from the homogenization section to the head of the screw, these “steam particles”, in the process of shooting pressure relief expansion, like a fine impurity of hard particles, produce friction damage on the wall. In addition, for some types of plastics, at high temperatures and pressures, moisture may act as a catalyst to promote cracking and create harmful impurities that can corrode metal surfaces. Therefore, the drying work before injection molding not only directly affects the quality of parts, but also affects the service life of the screw.