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Working Principle of Injection Machine

The working principle of Injection Machine is similar to the syringe used for injection. It uses the thrust of the screw (or plunger) to inject the plasticized molten state (that is, viscous flow) into the closed mold cavity.

Injection molding is a cyclic process, each cycle mainly includes: quantitative feeding-melt plasticization-pressure injection-mold filling cooling-mold take-out. After removing the plastic parts, the mold is closed again for the next cycle.

Injection Machine operation project: The Injection Machine operation project includes three aspects: control keyboard operation, electrical control system operation and hydraulic system operation. Select the injection process action, feeding action, injection pressure, injection speed, ejection type selection, temperature monitoring of each section of the barrel, adjustment of injection pressure and back pressure, etc.

The molding process of a general screw Injection Machine is: first, granular or powder plastic is added to the barrel, and the plastic is melted by the rotation of the screw and the outer wall of the barrel, and then the machine closes the mold and the injection seat moves forward. Keep the nozzle close to the gate of the mold, and then feed the injection cylinder with pressure oil to advance the screw, so that the molten material is injected into the closed mold with a lower temperature at a high pressure and a faster speed. Time and pressure are maintained (also known as holding pressure), cooling, and solidification, and the product can be opened to remove the product (the purpose of holding pressure is to prevent the backflow of the melt in the mold cavity, supplement the material into the mold cavity, and ensure the product Have a certain density and dimensional tolerance). The basic requirements of injection molding are plasticization, injection and molding. Plasticization is the prerequisite for achieving and ensuring 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, a correspondingly high pressure is generated in the mold cavity (the average pressure in the mold cavity is generally between 20 and 45 MPa), so there must be a sufficiently large mold clamping force. It can be seen that the injection device and the mold clamping device are the key components of Injection Machine.