The screw and barrel of the extruder are the core components of the extruder. Their combination is related to the working quality of the extruder, the plasticizing ability of the material and the production efficiency.
Therefore, when the extruder screws and barrels are severely worn, it will affect the output of the extruder. It can be seen that the maintenance of the screw and barrel is very important.
So, what are the reasons for the damage of the extruder screw and extruder barrel?
1. The extruder screw rotates in the barrel, and the friction between the material and the two causes the working surface of the extruder screw and extruder barrel to gradually wear; the diameter of the extruder screw gradually decreases, and the diameter of the inner bole of the barrel gradually increases. Therefore, with the gradual wear of the two, the matching diameter gap between the extruder screw and the extruder barrel will hardly increase.
However, since the resistance of the head of the barrel and the septum is unchanged, when the extruded material advances, the leakage flow will increase, that is, the amount of material flowing from the diameter gap to the feeding direction increases.
As a result, the output of the extruder is reduced. This phenomenon leads to an increase in the residence time of the material in the barrel, which leads to decomposition of the material. In the case of polyethylene, the hydrogen chloride gas produced by the decomposition will increase the corrosion of the screw and barrel of the extruder.
2. If the materials of extruder screw and extruder barrel contain fillers such as calcium carbonate and glass fiber, it may accelerate the wear of the extruder screw and extruder barrel.
3. Because the extruder screw material cannot be plasticized uniformly, or metal foreign matter is mixed into the material, the torque of the extruder screw increases suddenly. This torque exceeds the strength limit of the extruder screw, resulting in damage to the extruder screw. This is not a regular accident damage.