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Classification And Working Principle of Injection Molding Machine

Mar. 22, 2021


Here is the classification and working principle of the injection molding machine shared by the Injection Molding Machine Supplier. I hope it will be helpful to everyone.


Injection Molding Machine

Injection Molding Machine

Classification and usage


The injection molding machine has the ability to mold plastic products with complex appearance, precise size or dense texture with metal inserts at one time. It is widely used in national defense, electromechanical, automobile, transportation, building materials, packaging, agriculture, culture, education and health. All areas of people’s daily lives. With the rapid development of the plastics industry today, injection molding machines occupies an important position in terms of quantity and variety, and their total production accounts for 20%-30% of the entire plastic molding equipment, making it the fastest growing among plastic machinery at present. One of the most popular models.


Working principle


The working principle of the Injection Molding Machine is similar to the syringe used for injection. It uses the thrust of the screw to inject the plasticized and molten plastic into the closed mold cavity, and obtain the product after solidification and shaping.


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


The general molding process of a screw injection molding machine is: first add granular or powdered plastic into the barrel, and turn the screw and heat the outer wall of the barrel to make the plastic into a molten state, 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, so as to inject the melt into the closed mold with a lower temperature at a high pressure and a faster speed. Time and pressure are maintained and cooled to solidify and shape, then the mold can be opened and the product can be taken out.


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, so there must be a large enough clamping force. It can be seen that the injection device and the clamping device are the key components of the injection molding machine.


There are three main aspects to the evaluation of plastic products. The first is the appearance quality, including completeness, color, gloss, etc.the second is the accuracy between the size and relative position; the third is the physical properties, chemical properties, and Electrical performance, etc. These quality requirements are different depending on the use occasions of the products, and the required scales are also different. The defects of the product mainly lie in the design of the mold, the manufacturing accuracy and the degree of wear. But in fact, the technicians of plastic processing plants often suffer from the difficult situation of using technological means to compensate for the problems caused by mold defects without great results.


The adjustment of the process in the production process is a necessary way to improve the quality and output of products. Because the injection cycle itself is very short, if the process conditions are not well mastered, there will be an endless stream of waste products. When adjusting the process, it is best to change only one condition at a time and observe a few more times. If the pressure, temperature, and time are adjusted together, it is easy to cause confusion and misunderstanding. If there is a problem, I don't know the reason. There are many ways to adjust the process. In addition, attention should be paid to the dialectical relationship in the solution. For example: when the product has a depression, sometimes the material temperature must be increased, sometimes the material temperature must be lowered; sometimes the material quantity must be increased, and sometimes the material quantity must be reduced. It is necessary to recognize the feasibility of reverse measures to solve the problem.


The company provides Vertical Injection Molding Machines and automatic injection molding machines, please feel free to contact us if necessary


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