Resin pressure has a great influence on the shrinkage rate of metal injection molding. If the resin pressure is large, the shrinkage rate decreases and the product size is large. Even in the same cavity, the resin pressure varies with the shape of the product, resulting in different shrinkage rates. In the case of multiple cavity, the resin pressure in each cavity is likely to be different, and the shrinkage rate of each cavity is also different.

Mold temperature. Whether it is non - crystalline resin or crystalline resin, the mold temperature, the shrinkage rate will increase. Precision molding to maintain the mold temperature at a specific temperature. In the mold design, must pay attention to the cooling circuit design.

In general, the shrinkage rate changes when the gate area is changed. Shrinkage rate decreases with gate size, which is related to resin fluidity.

Wall thickness. Wall thickness also affects yield. For the non-crystalline resin, because the resin has different influence tendency on the shrinkage rate of the wall thickness, the wall thickness is larger, the shrinkage rate is also larger, and conversely, the shrinkage rate is smaller. For crystalline resin, the wall thickness must be avoided to change too much. In the case of multicavity, if the cavity wall thickness is different, the shrinkage rate will also be different.

Reinforcement material content. When glass fiber reinforced resin is used, the more glass fiber is added, the smaller the shrinkage rate. The shrinkage rate of metal injection molding in the flow direction is smaller than the transverse shrinkage rate. According to the difference of resin, the position of the sprue shape and the number of sprue must be considered in order to prevent twisting and warping.