The extruder screw and barrel are the soul components o […]
The extruder screw and barrel are the soul 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 screw screw and barrel for extruder and barrel are severely worn, the output of the extrusion is affected. It can be seen that the maintenance and repair of the screw barrel is very important!
Causes of damage to the extruder screw and barrel
The screw of the extruder rotates in the barrel, and the friction between the material and the two causes the working surface of the extruder screw and the barrel to wear gradually: the diameter of the screw of the extruder is gradually reduced, and the diameter of the inner hole of the barrel is gradually increased. Thus, the matching diameter gap between the extruder 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 extruder screw and barrel.
Filling materials such as calcium carbonate and glass fiber can accelerate the wear of the extruder screw and barrel.
Since the material is not plasticized uniformly, or metal foreign matter is mixed into the material, the torque of the extruder screw is suddenly increased. This torque exceeds the strength limit of the extruder screw, and the extruder screw is broken. This is an unconventional accident damage.
Its wear resistance directly affects production costs and product quality. Currently, 6542 high-speed steel and C-type sleeves are commonly used on the market. The service life of the two is generally only 3 months, and it needs to be replaced even in a few days when producing some hard materials.