1.Back pressure is too high: If the back pressure is set too high, then the screw may not be able to forward enough melt pressure to overcome the back pressure of the back pressure, the screw will not rotate back in a certain direction, so It will do more work on the melt and significantly increase the melt temperature, thus affecting the quality of the finished product and the effect of the helium on the cycle time.
2.Overheating or undercooling in the second half of the barrel: At the back of the feeding section, the material forms a thin layer of molten polymer during the heating process. The molten film is attached to the barrel. Without this thin layer, pellets are difficult to transport forward. The material in the feed section must be heated to a critical temperature to produce the critical melt film. However, it is often the case that the material stays in the barrel too short for the polymer to reach this temperature. This condition may be due to the small size of the equipment and the correspondingly smaller barrels and screws. If the residence time is too short, the polymer melts or the mixing is insufficient, which may cause the screw to slip or stall.
3.barrel or screw wear: the same with the feeding section, when the resin is melted in the screw tightening section is adhered to the barrel wall. When the screw is rotated, the material is sheared off the wall of the barrel and transported forward. If there is a wear zone on the screw and barrel, then the screw cannot effectively move the material forward.
4.Inadequate hopper planning: The correct hopper planning is the key to ensuring safe transportation of materials. In general, new pellets of uniform size operate well in a square hopper containing a flared zone. However, this is not the case when participating in recycled materials. By destroying the shape and size of the pellets again it is not common, which affects the uniformity of the feed. Incoherent feed means that the screw does not adhere to the uniform delivery pressure on the melt and slippage occurs.
5.When processing hygroscopicity data: Incorrect drying of material will significantly reduce the viscosity of the data in the barrel and the occurrence of water vapor, making it difficult for the screw to transport the material forward.
6.The failure of the check-return ring: When the screw is rotating and plasticizing the material, the check-return ring should be in the front position and contact the fixed ring seat. If the check ring is in a backward state, or in a state between forward and backward, the molten polymer will have resistance when it passes through the gap between the check ring and the ring seat. If you suspect there is a problem with the reverse loop, replace it immediately.