The working principle of the injection molding machine

The working principle of the injection molding machine is similar to that of the syringe used for injection, it is with the help of the thrust of the screw (or plunger), the plasticized molten state (i.e., viscous flow state) of the plastic is injected into the closed mold cavity, and then the products are obtained through the process of curing and shaping.

Injection molding is a cyclic process, each cycle mainly includes: dosing – melting and plasticizing – pressure injection – mold cooling – open the mold to take parts. After taking out the plastic parts and then close the mold for the next cycle.

Injection molding machine operation project: injection molding machine operation project includes control keyboard operation, electrical control system operation and hydraulic system operation in three aspects. The injection process action, feeding action, injection pressure, injection speed, ejection type selection, barrel temperature monitoring, injection pressure and back pressure pressure adjustment.

General screw injection molding machine molding process is: first of all, granular or powdered plastic into the barrel, and through the rotation of the screw and the outer wall of the barrel heating so that the plastic becomes molten, and then the machine for the mold and the injection seat forward, so that the nozzle is close to the mold’s gate channel, and then to the injection cylinder through the pressure of the oil, so that the screw forward so that a very high pressure and high speed will be injected into the molten material at a low temperature of the Closed mold, after a certain period of time and pressure to maintain (also known as holding pressure), cooling, so that the solidification of the mold, you can open the mold to take out the product (the purpose of holding pressure is to prevent backflow of the melt in the mold cavity, to the cavity to supplement the material, as well as to ensure that the product has a certain density and dimensional tolerances). The basic requirements of injection molding are plasticization, injection and molding. Plasticization is a prerequisite to achieve and ensure the quality of molded products, and in order to meet the requirements of molding, injection must ensure that there is sufficient pressure and speed. At the same time, due to the high injection pressure, the corresponding high pressure in the mold cavity (the average pressure in the mold cavity is generally between 20 ~ 45MPa), so there must be a large enough clamping force. It can be seen that the injection device and mold closing device are the key components of the injection molding machine.

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