The working principle of the injection molding machine is similar to the principle of the syringe. Under the push of the screw, the plastic is injected into the closed mold cavity, and the process of curing and shaping the product is obtained in the closed mold cavity. This process mainly includes four stages, which are: filling, pressure holding, cooling and demoulding, which is a complete and continuous process. Below, Xiaobian tell you about the specific production process of the injection molding machine.

1. Filling

The first step in the injection molding process is to fill, and the speed of filling directly affects the efficiency of the molding, which can be divided into high-speed filling and low speed filling. Generally, the weld mark strength is better in the high temperature region. Under the condition of high temperature, the chain activity of polymer is better, the thermodynamic properties of melt are basically the same, and the strength of fusion zone increases. On the contrary, low temperature welding strength is poor.

2. Maintain pressure

In the pressure holding stage, continuous pressure is applied to the melt in order to increase the density of the plastic and avoid the shrinkage of the plastic as far as possible. During the pressure holding process, the plastic flow rate is low, the flow no longer plays a leading role, and the pressure holding process is mainly affected by pressure factors. In the area of high pressure, the plastic will be more dense, while the low area will be loose, and the density distribution of each part is different. During the pressure holding process, the plastic has been filled with the mold cavity, and there is a tendency to open the mold under pressure. Therefore, when choosing an injection molding machine, try to choose a large clamping force to effectively ensure pressure preservation.

Third, the cooling stage

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 are the design of the plastic product, the mold material, the configuration of the cooling water pipe and the nature of the coolant. Pay attention to set the rules of the cooling system to ensure that the cooling effect is uniform and rapid

Four, demoulding stage

This part is the last part of injection molding. At this time, the product is cold solid forming and the demoulding method is improper, which will cause the uneven stress of the product and cause deformation. The demoulding methods mainly include ejector rod demoulding and stripper plate demoulding. The specific choice of demoulding method depends on the structural characteristics of the product.