Due to the different materials of each product, the occurrence of defective products in the injection molding process often occurs. For example, rigid plastic products often have shock marks, so what is the reason?

Causes of shock marks in products during injection molding:

On the surface near the gate of rigid plastic parts such as PS, dense ripples are formed around the gate, sometimes referred to as chatter marks. The reason is that when the melt viscosity is too large and the mold is filled in a stagnation form, the material at the front end quickly condenses and shrinks as soon as it contacts the surface of the cavity, and the subsequent melt expands the contracted cold material and continues the process Continuous alternation causes the material flow to form surface ripples as it progresses.

The solution to the occurrence of shock marks in the injection molding process:

(1) Increasing the barrel temperature, especially the nozzle temperature, should also increase the mold temperature.

(2) Increase the injection pressure and speed so that it can quickly fill the model cavity.

(3) Improve the size of runners and gates to prevent excessive resistance.

(4) The exhaust of the mold should be good, and a cold feed well large enough should be set.

(5) Do not design the parts too thin.