The combined work quality of the two parts, the screw and the barrel, has an important influence on the plasticization of the material, the quality of the product and the production efficiency. Their quality of work is related to the manufacturing precision and assembly clearance of the two parts. When the two parts are seriously worn and the output of the extruder is reduced, the maintenance of the screw and the barrel should be arranged. Below, Xiaobian will give you a brief introduction to the analysis of the vulnerable parts of the twin-screw extruder:
1. The screw rotates in the barrel, and the friction between the material and the two causes the working surface of the screw and the barrel to wear gradually: the diameter of the screw is gradually reduced, and the diameter of the inner hole of the barrel is gradually increased. Thus, the matching diameter gap between the screw and the barrel increases little with the gradual wear of the two. However, since the resistance of the front head and the splitter plate of the barrel is not changed, this increases the leakage flow when the extruded material advances, that is, the amount of material flowing from the diameter gap to the feed direction increases. As a result, the extruder production is reduced. This phenomenon causes the residence time of the material in the barrel to increase, causing the material to decompose. In the case of polyethylene, the hydrogen chloride gas produced by the decomposition enhances the corrosion of the screw and the barrel.
2. Since the material is not plasticized evenly, or metal foreign matter is mixed into the material, the torque of the screw is suddenly increased. This torque exceeds the strength limit of the extruder screw, and the screw twisting accident is an unconventional The accident was damaged.
3. If there are fillers such as calcium carbonate and glass fiber in the material produced by the crusher, the wear of the screw and the barrel can be accelerated.
