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Working principle of injection molding system

Update:06-12-2019
Summary:

The working principle of the injection molding machine […]

The working principle of the injection molding machine is similar to the injection syringe. It uses the thrust of the screw (or plunger) to inject the plasticized molten state (ie, viscous flow state) into the closed mold cavity. The process of obtaining products after curing and setting.

Injection molding is a cyclic process, and each cycle mainly includes: quantitative feeding-melt plasticization-pressure injection-filling cooling-opening and taking parts. After removing the plastic part, the mold is closed and the next cycle is performed.

Injection molding machine operation items: Injection molding machine operation items include control keyboard operation, electrical control system operation, and hydraulic system operation. The injection process action, feeding action, injection pressure, injection speed, ejection type selection, temperature monitoring of each section of the barrel, and adjustment of injection pressure and back pressure are performed separately.

The molding process of a general screw injection molding machine is: firstly add granular or powdered plastic into the barrel, and then turn the screw and the outer wall of the barrel to make the plastic into a molten state, and then the machine performs the mold clamping and injection seat forward, Keep the nozzle close to the gate of the mold, and then pass pressure oil into the injection cylinder to advance the screw, so that the melt is injected into the closed mold with a lower temperature at a higher pressure and faster speed. Time and pressure are maintained (also known as holding pressure), cooling, solidifying and forming, and the product can be opened to remove the mold. With certain density and dimensional tolerances). The basic requirements of injection molding are plasticization, injection and molding. Plasticization is a prerequisite for achieving and guaranteeing the quality of molded products. To meet the requirements of molding, injection must ensure 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 it must have a sufficient clamping force. It can be seen that the injection device and the mold clamping device are the key components of the injection molding machine.

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