Five causes of screw wear:

1, each plastic, there is an ideal plastic processing temperature range, the barrel processing temperature should be controlled to make it close to the temperature range.
Granular plastic from the hopper into the barrel, the first will reach the feeding section, in the feeding section is bound to appear dry friction, when these plastics are not hot enough, melting uneven, it is easy to cause the inner wall of the barrel and screw surface wear increased.
Similarly, in the compression section and homogenization section, if the plastic molten state disorder uneven, will also cause wear faster.

2. Speed should be adjusted properly.
Some plastics are fortified with additives such as fiberglass, minerals, or other fillers.
These substances tend to have a much greater friction on the metal than on molten plastic.
In the injection molding of these plastics, if the high speed into, then in the improvement of the shear force on plastic at the same time, but also will strengthen the corresponding production of more torn fiber, torn fiber contains a sharp end, the wear force greatly increased.
Inorganic minerals in the metal surface at high speed sliding, its scraping effect is not small.
So the speed should not be set too high.

3. When the screw rotates in the barrel, the friction between the material and the two causes the working surface of the screw and the barrel to gradually wear down: the diameter of the screw is gradually reduced, and the diameter of the inner hole of the barrel is gradually increased.
In this way, the diameter clearance of screw and barrel increases with the gradual wear of both.
However, due to the barrel in front of the head and the shunt plate resistance did not change, this increased the extrusion material forward leakage flow, that is, the material from the diameter of the clearance to the direction of the flow momentum increased.
As a result, plastic machinery production decreased.
This phenomenon also increases the retention time of materials in the barrel, resulting in material decomposition.
In the case of polyethylene, the decomposition of hydrogen chloride gas enhances the corrosion of the screw and cylinder.

4. Filling materials such as calcium carbonate and glass fiber can accelerate the wear of screw and barrel.

5. Because the material is not plasticized evenly or there is metal foreign matter mixed into the material, the rotating torque force of the screw will suddenly increase, which exceeds the strength limit of the screw and causes the screw to break.
This is an unusual accident damage.