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Working principle of injection molding machine

Working principle of injection molding machine

Oct 22,2020
Working principle of injection molding machine
      Injection molding machine is also called injection molding machine or injection machine. It is the main molding equipment for making thermoplastic or thermosetting plastics into various shapes of plastic products through plastic molding molds. Including vertical, horizontal, and all-electric. The injection molding machine can heat the plastic and apply high pressure to the molten plastic to inject it to fill the mold cavity. Now let the editor take you to understand the working principle of the injection molding machine.
working principle

     The injection molding machine and the syringe used for injection have a relatively similar working principle. It is a process in which the plasticized molten state (ie, viscous flow state) plastic is injected into the closed mold cavity by the thrust of the screw (or plunger), and the product is obtained after solidification and shaping.
     The injection molding process is a cycle. Quantitative feeding-melting and plasticizing-pressure injection-mold filling and cooling-mold opening and picking are the main contents of each cycle. After taking out the plastic part, the mold is closed again for the next cycle. Control three aspects including keyboard operation, electrical control system operation and hydraulic system operation. Respectively adjust the injection pressure and back pressure, monitor the temperature of each section of the barrel, and select the injection process action, feeding action, injection pressure, injection speed, ejection type, etc.

    First, add granular or powdered plastic into the barrel. The plastic is melted by the rotation of the screw and the outer wall of the barrel. Then the machine closes the mold and moves the injection seat forward, closes the nozzle at the gate of the mold, and then presses The oil is passed into the injection cylinder and the screw is pushed forward, thereby injecting the melt into the closed mold with a lower temperature at a high pressure and a faster speed. After a certain period of time and pressure holding (also called pressure holding), cooling, and solidifying it, the product can be opened and taken out. (To ensure that the product has a certain density and dimensional tolerances, it is the purpose of maintaining pressure to supplement the material in the cavity to avoid the reflux of the melt in the cavity). Plasticization, injection and molding are the basic requirements of injection molding. The prerequisite for realizing and ensuring the quality of molded products is plasticization. Injection must ensure sufficient pressure and speed in order to meet the molding requirements. At the same time, because there is a high injection pressure, there is a high pressure correspondingly generated in the cavity (20-45MPa is usually the average pressure in the cavity), so there must be a sufficient clamping force. This shows that the key components of the injection molding machine are the injection device and the mold clamping device.