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Damage to the screw and barrel

Update:22 Mar 2019

1. The screw rotates in the barrel, and the friction be […]

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 travels, that is, the amount of movement of the material from the diameter gap to the feed direction increases. As a result, the extruder consumption drops. This phenomenon in turn increases the residence time of the material in the barrel and forms a material synthesis. In the case of polyethylene, the hydrogen chloride gas produced by the synthesis enhances the corrosion of the screw and the barrel.

2. If there are fillers such as calcium carbonate and glass fiber in the material, it can accelerate the wear of the screw and the barrel.

3. Since the material has no plasticized average, or there is metal foreign matter mixed into the material, the torque of the screw is suddenly increased. This torque exceeds the strength limit of the screw, and the screw is broken. This is a very accidental damage.

4. The degree, straightness and clearance of the screw and barrel device are not adjusted in place, and the fastening screws are not reinforced. At the time of starting, the screw barrel has friction, which accelerates the damage of the screw barrel.

5. There is a lack of preheating time before starting the machine. The raw materials accumulated in the screw barrel are not fully softened, the starting torque is too large, or there is a large piece of unsoftened material, which causes the screw barrel to sprain or break. Damage to the gearbox is formed.