Production Process and Working Principle of Injection Molding Machine
The working principle of the injection molding machine is similar to that of the syringe. With the help of the thrust of the screw, the plasticized plastic in the molten state is injected into the closed mold cavity, and the product is obtained after solidification and setting. This process mainly includes four stages, namely: filling, holding pressure, cooling, and demoulding, which is a complete and continuous process. Next, Powerjet Group will tell you about the specific production process of injection molding machines.
The first step in the injection molding process is filling. The speed of filling directly affects the efficiency of molding. It can be divided into high-speed filling and low-speed filling. Generally, the weld line strength is better in the high-temperature zone. In a high temperature environment, the polymer chain has better mobility, and the thermal properties of the melt are almost the same, which increases the strength of the welded area. On the contrary, the low temperature welding strength is poor.
2. Keep Pressure
In the pressure holding stage, continuous pressure is applied to the melt in order to increase the density of the plastic and try to avoid the shrinkage of the plastic. During the pressure holding process, the plastic flow rate is low, and the flow no longer plays a leading role. The pressure holding process is mainly affected by pressure factors. In the high pressure area, the plastic will be denser, and the low area will be looser, and the density distribution of each part will be different. In the process of holding pressure, the plastic has been filled in the mold cavity, and the mold has a tendency to open under the pressure. Therefore, when choosing an injection molding machine, try to choose a large clamping force to effectively ensure the pressure holding.
In the entire molding cycle, the cooling time accounts for about 70%-80%, which directly affects the output of plastic products. The factors that affect the cooling of the product include the design of the plastic product, the mold material, the configuration of the cooling water pipe, and the nature of the cooling liquid. Pay attention to the rules of setting up the cooling system to ensure that the cooling effect is uniform and rapid
4. Demoulding Stage
This link is the last link of injection molding. At this time, the product is cold-solidified and the demoulding method is improper, which will cause the product to be deformed due to uneven force. The demoulding methods mainly include ejector demoulding and stripping plate demoulding. Which demolding method to choose depends on the structural characteristics of the product.