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Working Principle and Operation of Plastic Molding Machine

The working principle of the Plastic Molding Machine is similar to that of a syringe for injection. It uses the thrust of the screw (or plunger) to inject the plastic that has been plasticized in a molten state (that is, a viscous fluid state) into the closed 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 - mold filling and cooling - mold opening and picking. After taking out the plastic parts, the mold is closed again, and the next cycle is carried out.   

1) Lock and close the mold: the mold puller approaches the fixed mold pulley quickly (including slow-fast-slow speed), and after confirming that there is no foreign matter, the system turns to high pressure to lock the template (maintain the pressure in the cylinder).  

2) The injection platform moves forward: the injection platform advances to the specified position (the nozzle and the mold are in close contact).  

3) Plastic injection molding: The screw can be set to multi-stage speed, pressure and stroke to inject the molten material at the front end of the barrel into the cavity.  

4) Cooling and holding pressure: According to the set pressure and time period, the pressure of the barrel is maintained, and the mold cavity is cooled and formed at the same time.  

5) Cooling and pre-molding: The product in the mold cavity continues to cool, and at the same time the hydraulic motor drives the screw to rotate to push the plastic particles forward, and the screw retreats under the control of the set back pressure. When the screw retreats to the predetermined position, the screw stops rotating and the injection of The oil cylinder is loosened and retreated according to the setting, and the forecast is over.  

6) The injection platform retreats: After the pre-molding is completed, the injection platform retreats to the designated position.       

7) Mold opening: the mold puller moves back to its original position (including slow-fast-slow speed).       

8) Ejection: The thimble ejects the product. The basic requirements of injection molding are plasticization, injection and molding. Plasticization is the prerequisite to realize and guarantee the quality of molded products, and in order to meet the requirements of molding, injection must ensure sufficient pressure and speed. At the same time, due to the high injection pressure, correspondingly high pressure is generated in the mold cavity (the average pressure in the mold cavity is generally between 20 and 45MPa), so there must be a sufficient clamping force. It can be seen that the injection device and the clamping device are the key components of the injection molding machine.

Ningbo Salai machinery co.,Ltd. not only has Plastic Molding Machine but also Small Injection Molding Machine and other products, welcome to visit our official website.

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