Key Mold Design Requirements for Precision Injection Molding

For precision injection molding, the mold cavity and runner system must be made from materials that have undergone strict heat treatment. Mold steel should be selected with high mechanical strength, high hardness, good wear resistance, and strong corrosion resistance. In general, the hardness of the molding components should reach approximately HRC 52 to ensure stable performance and long mold life.

In mold structure design, the number of cavities should not be excessive. The bottom plate, support plate, and cavity walls should be made thicker where necessary to prevent severe elastic deformation of the mold components under high temperature and high injection pressure.

Whenever possible, precision molds should use a relatively small number of cavities, short and simple flow paths, and a higher surface finish than conventional molds. These design features help improve filling performance, reduce flow resistance, and support easier demolding.

The dimensional accuracy of precision plastic parts depends mainly on the dimensional accuracy of the mold cavity, the positioning accuracy of the cavity inserts, and the accuracy of the parting surface. Important design considerations also include whether the plastic part geometry is easy to manufacture, whether the gate design provides good filling performance, and whether the cooling system can cool the mold evenly and efficiently.

For general precision injection molds, the mold dimensional tolerance should be controlled to a level higher than the required product dimensional tolerance, so that the molded parts can consistently meet accuracy requirements in mass production.