The working principle of the injection molding machine is similar to that of the syringe for injection. It is to inject the plasticized molten state (ie, the viscous flow state) into the closed cavity by the thrust of the screw (or plunger). The process of obtaining the product after curing and setting.
Injection molding is a cyclic process, and each cycle mainly includes: quantitative feeding – melt plasticizing – pressure injection – filling mold cooling – mold extraction. After removing the plastic part, the mold is closed again for the next cycle.
Injection molding machine operation items: Injection molding machine operation items include three aspects: control keyboard operation, electrical control system operation and hydraulic system operation. The injection process action, the feeding action, the injection pressure, the injection speed, the selection of the ejection type, the monitoring of the temperature of each section of the barrel, the adjustment of the injection pressure and the back pressure are performed.
Generally, the molding process of the screw type injection molding machine is: firstly, the granular or powdered plastic is added into the barrel, and the plastic is melted by the rotation of the screw and the outer wall of the barrel, and then the machine performs the mold clamping and the injection seat forward. The nozzle is placed close to the gate of the mold, and then the pressure oil is introduced into the injection cylinder to advance the screw, thereby injecting the melt into the lower temperature closed mold at a high pressure and a relatively high speed. Time and pressure are maintained (also known as holding pressure), cooled, and solidified, and the product can be opened by mold opening (the purpose of holding pressure is to prevent backflow of molten material in the cavity, replenish material into the cavity, and ensure the product Has a certain density and dimensional tolerance). The basic requirements for injection molding are plasticization, injection and molding. Plasticization is the premise to achieve and guarantee the quality of molded products, and in order to meet the molding requirements, the 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 cavity (the average pressure in the cavity is generally between 20 and 45 MPa), so a sufficient clamping force must be obtained. It can be seen that the injection device and the clamping device are key components of the injection molding machine.