Sprue design of injection molds
Sprue is the part of the injection mold where the melted plastic enters the cavity first, which leads the melted plastic into the runner and cavity. Generally, the sprue is conical in shape to facilitate the flow of the melt material.
The shape and size of the sprue affect the flow rate and filling time of the plastic. Considering that the sprue needs to be in contact with melt plastic and molding machine nozzle repeatedly, usually the sprue is designed as a separate sleeve embedded in the cavity plate.
The design skills of the sprue of injection mold are as follows:
1.To facilitate the pulling out of the condensed material from the sprue, the sprue is designed in a conical shape.
2.The end of the sprue is designed to be round, the radius of the corner can be 1-3mm, which can reduce the resistance of the material flow.
3.The length of the sprue should be as short as possible to avoid injection pressure loss, thereby improving the product quality.
4.To make the molten plastic completely flowing into the sprue, the sprue should close contact with the nozzle, and the docking hemisphere is always the first option to achieve the function.
