The cause of shrinkage pit is the same as that of insufficient filling In principle, it can be solved by excess filling, but there is a risk of stress The wall thickness should be uniform in design, and the wall thickness of stiffeners, convex columns and other places should be reduced as much as possible. The treatment of overflow should focus on the improvement of the mold. In terms of molding conditions, we can start with reducing liquidity.

The following methods can be used:
(1) Reduce the injection pressure.
(2) Reduce the resin temperature.
(3) Select materials with high viscosity grade.
(4) Lower the mold temperature.
(5) Grind the mold surface where the overflow occurs.
(6) Use harder die steel.
(7) Improve the clamping force.
(8) Adjust the joint surface and other parts of the accurate mold.
(9) Add mold support column to increase rigidity.
(10) Determine the size of different exhaust grooves according to different materials.