Common causes of wear

1. Every plastic has an ideal plasticizing temperature range, and the barrel processing temperature must be controlled to reach this temperature range. Granular plastic enters the barrel from the hopper and reaches the feeding section first. Dry friction essentially takes place in the feeding section. If these plastics are not heated enough and do not melt unevenly, it is easy to increase the wear of the inner wall of the barrel. Barrel and screw surface. Similarly, compression and homogenization sections wear faster when the plastic melts.

2. Speed ​​should be properly adjusted. This is because some plastics have added reinforcing agents like fiberglass, minerals and other fillers. These materials reduce metal much more than molten plastic. When injection molding these plastics, the use of high rpm increases the shear forces on the plastic and likewise other chopped fibers. Chopped fibers have sharp tips. This causes wear and tear. The power of the tear is greatly increased. When the inorganic mineral slides on the metal surface at high speed, the scraping effect is not small. So don't adjust the speed too much.

3. The screw rotates in the barrel, and the working surface of the screw and barrel is gradually worn due to the friction between the material and the two. The diameter of the screw is gradually reduced, and the diameter of the hole inside the barrel is gradually reduced and gradually increased. Thus, the gap between the screw and the matching diameter of the barrel gradually increases as they wear out. However, since the resistance of the manifold before the nose and barrel is unchanged, this increases the leakage flow of the exiting material as it advances, i.e., the flow of material from the diameter gap in the feed direction. As a result, production of plastic machinery declined. This phenomenon increases the residence time of the material in the barrel, resulting in material decomposition. In the case of polyvinyl chloride, hydrogen chloride gas produced by decomposition promotes corrosion of screws and barrels.

4. Filler materials such as calcium carbonate and glass fiber can cause premature wear of screws and barrels.

5. Because the material is not uniformly plasticized or the material is mixed with metal foreign matter, the screw rotation torque will increase rapidly, and the torque will exceed the strength limit of the screw, which will cause the screw to break. This is an exceptional accidental loss.