During the injection molding process, exhaust gas can be exhausted from the mould. The exhaust system of a mold has a complicated structure. The exhaust system has the ability to connect in different directions. Therefore, the position of the exhaust system is very important. The position of the exhaust system in the mold has a direct influence on the forming cycle.

The exhaust system of a mold can be used to reduce vibrations, improve the quality of the product and facilitate installation. However, the exhaust system of a mold is affected by moisture content, volatiles, and the presence of impurities. These impurities can have a negative effect on the quality of the product and reduce the mechanical strength of the mold. Therefore, the exhaust system of a mold needs to be designed accordingly.

The exhaust pipe mould is divided into three parts: the mold cavity, the cross gate, and the water gaps. The water gaps are connected with the mold cavity through the riser. The riser has an inclined upper wall surface and a downward-sloping lower wall surface. It is arranged at the junction between the cross gate and each water gap. The riser also extends down to the mold cavity. In addition, each set of molds must use open exhaust grooves. Compared to closed exhaust grooves, open exhaust grooves have the largest exhaust volume. In addition, they are the easiest to process.

The insert structure of a mold is required in order to eliminate the phenomenon of trapped air. The insert structure has two small recesses, which fit along with the fitting position of the small insert head. The small insert head is fitted to the recesses of the mold and discharges the trapped air out of the mold when the material flows to the points.

Usually, the process insert design is used when the exhaust requirements are high. However, the insert structure needs to be designed in order to prevent the phenomenon of trapped air from forming. If the insert structure is designed in an incorrect way, the flow material can be incorrectly placed and the exhaust system can be positioned incorrectly. In addition, it can lead to negative dimensional accuracy and poor mechanical strength. In addition, it can also lead to flow marks and fusion marks.