What Is The Relationship Between The Shrinkage Of Injection Molded Products And Injection Plastic Molds

1. The structure of the injection plastic mold affects the shrinkage of the injection product

The gate type of the plastic injection mold has an effect on the shrinkage of the injection product. When using small gates, the shrinkage of the plastic parts increases because the gate has solidified before the end of the holding pressure. The cooling circuit structure of the plastic injection mold is the key to the design of the injection mold. If the cooling ring is improperly designed, it will cause a difference in shrinkage due to the unbalanced temperature around the plastic part, which will cause the product to be out of size or deformed. In thin-walled parts, the mold temperature has a more significant effect on the shrinkage rate.

2. The parting surface and gate of the injection plastic mold affect the shrinkage of the injection product

The parting surface, gate pattern and size of the plastic injection mold will directly affect the direction of the plastic material flow, the density distribution, the pressure-holding and shrinking effect and the molding time.

The use of straight gates and large cross-section gates can reduce shrinkage, but in the case of greater anisotropy, straight gates and large cross-section gates shrink along the flow direction of the molten plastic, and shrink more along the vertical flow direction; on the contrary, When the gate thickness is small, the gate part of the injection plastic mold will condense and solidify in advance, and the plastic in the cavity cannot be refilled with molten plastic after shrinking, which will cause the product to shrink more.

The point gate cools and solidifies faster. When the conditions of the injection molded part allow, you can set multiple gates on the plastic injection mold. This can effectively increase the holding time, increase the mold cavity pressure, and reduce the shrinkage of the product. rate.