For the repair of the barrel screw, if the inner surface of the barrel is worn or the scratch is not serious, it can be polished and polished on the lathe with oil stone or abrasive cloth. When the inner surface of the barrel is worn seriously, the depth of the wear groove should be checked first. Calculate whether there is a heat treatment hard layer on the inner wall of the barrel after removing the wear layer, and the surface of the inner hole of the barrel can be trimmed. After the grinding, the inner surface roughness Ra of the barrel should be no more than 1.6üm. Hole axis tolerance is precision machined according to GB1184-80. For example, after the mold is repaired, there is no heat treatment hard layer on the inner surface of the barrel. The alloy can be placed in the barrel. The centrifugal casting method can also be used to cast a layer of hard alloy on the inner wall of the barrel for machining and grinding.
Features of the barrel screw, wear resistance, long life, high temperature resistance, no deformation under high temperature. Corrosion resistant, materials are corrosive. Good cutting performance. High strength, can withstand high torque, high speed, low residual stress after heat treatment, small thermal deformation.
The forming process of the barrel screw is to first add the granular or powdered plastic into the barrel, and the plastic is melted by the rotation of the conical twin screw and the outer wall of the barrel, and then the machine performs the mold clamping and the injection seat to move forward, so that the nozzle Close to the gate of the mold, and then pass the pressure oil to the injection cylinder, so that the screw advances, so that the melt is injected into the lower temperature closed mold at a high pressure and a faster speed, after a certain time and The pressure is maintained (also known as pressure holding), cooled, and solidified, and the product can be opened by mold opening (the purpose of holding pressure is to prevent backflow of molten material in the cavity, replenish material into the cavity, and ensure that the product has certain Density and dimensional tolerance).
