For the repair of the barrel and screw, when the inner […]
For the repair of the barrel and screw, when the inner surface of the barrel is not severely worn or scratched, it can be polished and polished on the lathe with oilstone or emery cloth. When the inner surface of the barrel is severely worn, check the depth of the wear groove first, and calculate whether the inner wall of the barrel has a heat-treated hard layer after the wear layer is removed, and the surface of the inner hole of the barrel can be trimmed. After grinding, the inner surface roughness Ra of the barrel should not be greater than 1.6um. The tolerance of the hole axis is precision processed according to GB1184-80 level 7. If there is no heat treatment hard layer on the inner surface of the barrel after the mold is repaired, it can be matched with the gold sleeve in the barrel, or a centrifugal casting method can be used to cast a layer of cemented carbide on the inner wall of the barrel for use after machining and grinding.
The characteristics of the barrel and screw, wear resistance, long life, high temperature resistance, no deformation under high temperature. Corrosion resistance, the material is corrosive. Good cutting performance. High strength, can withstand high torque, high speed, small residual stress after heat treatment, small thermal deformation, etc.
The molding process of the barrel screw is to first add granular or powdered plastic into the barrel, and turn the screw and heat the outer wall of the barrel to make the plastic into a molten state, then the machine closes the mold and moves the injection seat forward to make the nozzle Close to the gate of the mold, and then pass pressure oil to the injection cylinder to push the screw forward, thereby injecting the melt into the closed mold with a lower temperature at a high pressure and a faster speed. After a certain time and Hold the pressure (also known as holding pressure), cool it to solidify and shape, and then the mold can be opened to take out the product (the purpose of holding pressure is to prevent the backflow of the melt in the cavity, replenish the material in the cavity, and ensure that the product has a certain Density and dimensional tolerances).