Damage reasons of bimetallic barrel and screw

When material is rotated between barrel and screw, the friction will make the surface wear. The diameter of screw gets smaller while the diameter of barrel inner hole gets bigger. So that the gap between barrel and screw will gets bigger with continuous wear. However, the resistance of cylinder front head and splitter board has not changed which increased the flow leakage of extruded material. As a result, the production of extruder will decline. This also increases remained time of material in the barrel, causing decomposition of materials. If it is polyethylene, decomposed hydrogen chloride will corrode the barrel and screw more seriously. Material such as calcium carbonate and glass fiber can accelerate the wear of barrel and screw. Another reason is other metal may be mixed with material. When screw rotates, torque suddenly will increase. If the torque exceeds the ultimate strength of screw, it will damage.

If you find barrel and screw are worn out or the production of extruder declines, you should arrange for a repair or replacement of bimetallic barrel and screw.