Working principle of Injection moulding machine

- Aug 20, 2018-

Injection molding machine working principle and injection syringe similar, it is the use of screw (or plunger) of the thrust, the plasticizing of the molten state (that is, viscous flow state) of plastic injection into a closed cavity, after the solidification of the process of obtaining products. Injection molding is a cycle of the process, each cycle mainly includes: quantitative feeding-melt plasticizing-pressure injection-mold cooling-open mold pickup.

Remove the plastic parts and then close the mold, for the next cycle. Injection Molding Machine Operation project: The Injection molding machine operation project includes the control keyboard operation, the electrical control system operation and the hydraulic system operation three aspects.

respectively, the injection process action, feeding action, injection pressure, injection speed, ejector type selection, barrel temperature monitoring, injection pressure and back pressure adjustment. General Screw Injection Molding machine Molding process is: first of all granular or powdered plastic into the barrel, and through the rotation of the screw and the outer wall of the barrel to make the plastic molten state, and then the machine for the mold and injection seat forward, so that the nozzle close to the gate of the die, and then into the injection cylinder into the pressure oil, so that the screw forward, The melt is injected into a closed die with a lower temperature at high pressure and at a faster rate, after a certain period of time and pressure to maintain (also known as pressure), cooling, so that its curing molding, you can open the mold out products (the purpose of holding pressure is to prevent the mold cavity in the flow of molten material, to the mold cavity to replenish the material, and ensure that the product has a certain density and dimensional tolerance). The basic requirements for injection molding are plasticizing, injection and moulding. Plasticizing 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, because the injection pressure is very high, the corresponding in the mold cavity produces very high pressure (in the mold cavity average pressure is generally between 20~45mpa), therefore must have the large enough clamping force.

Thus, the injection device and the clamping device are the key parts of the injection moulding machine. The evaluation of plastic products has three main aspects, the first is the appearance of quality, including integrity, color, gloss, etc. the second is the accuracy between the size and relative position, the third is the corresponding physical properties, chemical properties, electrical properties and so on. These quality requirements are based on the use of different products, the required scale is also different. The defects of the products mainly lie in the design of mould, the precision of manufacture and the degree of wear.

But in fact, plastic factory technicians often suffer from the face of the process to make up for the problems caused by mold defects and the difficult situation is not successful. The process adjustment in production process is the necessary way to improve the quality and yield of products. Because the injection cycle itself is very short, if the process conditions are not mastered, the waste will be endless. In the adjustment process is best to change only one condition at a time, to observe a few times, if the pressure, temperature, time all together, it is easy to cause confusion and misunderstanding, out of the question also do not know what the truth. The measures and means to adjust the process are manifold. For example: To solve the problem of product note dissatisfaction there are more than 10 possible solutions, to choose a solution to the crux of the brilliantly major solution, can really solve the problem. In addition, we should pay attention to the dialectical relationship in the solution. For example: Products appear in the SAG, sometimes to improve the material temperature, sometimes to reduce the material temperature, sometimes to increase the amount of material, sometimes to reduce the amount of material. The feasibility of solving the problem of reverse measures should be acknowledged.