The working principle of the injection molding machine is similar to the syringe used for injection. It uses the thrust of the screw (or plunger) to inject the plasticized plastic in the molten state (that is, the viscous fluid state) into the closed mold cavity. The process of obtaining the product after curing and shaping.
Injection molding is a cyclic process, and each cycle mainly includes: quantitative feeding-melting and plasticizing-pressure injection-mold filling and cooling-mold opening and picking. After taking out the plastic part, the mold is closed again for the next cycle.
Injection molding machine operation project: The injection molding machine operation project includes three aspects: control keyboard operation, electrical control system operation and hydraulic system operation. Carry out the injection process action, feeding action, injection pressure, injection speed, ejection type selection, temperature monitoring of each section of the barrel, injection pressure and back pressure adjustment, etc.
The molding process of a general screw injection molding machine is as follows: first add granular or powdered plastic into the barrel, and make the plastic into a molten state through the rotation of the screw and heating of the outer wall of the barrel, and then the machine closes the mold and moves the injection seat forward. Make the nozzle close to the gate of the mold, and then pass pressure oil into the injection cylinder to push the screw forward, thereby injecting the melt into the closed mold with a lower temperature at a high pressure and a faster speed. Time and pressure hold (also known as holding pressure), cooling to make it solidify and form, then the mold can be opened and the product can be taken out (the purpose of holding pressure is to prevent the reflux of the melt in the cavity, replenish the material in the cavity, and ensure the product With certain density and dimensional tolerances). The basic requirements of injection molding are plasticization, injection and molding. Plasticization is a prerequisite for realizing and ensuring 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, a correspondingly high pressure is generated in the cavity (the average pressure in the cavity is generally between 20 and 45 MPa), 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.