How to improve the use of screw barrel?
Injection Molding Screw Barrel is a long time in high temperature, high pressure, high mechanical torque and high friction environment for work. The first few factors are required by the process conditions, and the losses caused by friction are unavoidable. The general screw has been treated with surface nitriding to improve surface hardness, that is, to improve wear resistance. However, if the cause of wear and tear is neglected and the wear is not reduced, the working life of the screw will be greatly reduced.
The cause of screw wear and the method of reducing wear
1, each kind of plastic has an ideal temperature range of plasticizing. It should control the processing temperature of the cylinder to make it close to the temperature range. Granular plastic from the hopper into the barrel, the first will arrive at the feeding section in the feeding section will appear dry friction, when the shortage of these plastics are heated, melting, very easy to cause the barrel wall and screw surface wear. Similarly, in the compression section and homogenization section, if the melting state of plastic is uneven, it will cause wear and tear.
2, the speed should be adjusted properly. Because some plastics are reinforced, such as glass fiber, minerals or other fillings. The friction of these materials against metals is often much greater than that of molten plastics. In the plastic injection molding, if using high speed, the increase of shear stress on the plastic at the same time, will also strengthen the corresponding to produce more torn fibers, the torn fibers containing sharp ends, to wear a large force to increase. The scraping action of inorganic minerals on metal surface is not small at high speed. Therefore, the speed should not be adjusted too high.