Today we are continuing to discuss another case for the sink mark, we will show what we would do when we face the sink mark problem.

1. Basic information: ABS Case shrinkage

2. Description: 
a. Even if the maximum injection pressure is selected for molding, shrinkage will occur in the place where Rib is behind the molded part. 
b. As shown in picture, the cross-sectional area of the gate becomes small, causing a large pressure loss, and it is difficult to maintain the pressure on the back of the Rib portion, thereby causing shrinkage. And the submerged glue gate has a small hole diameter and the gate extension is thin. As a result, the pressure loss is large, the sealing time is short, and the pressure holding control is invalid. 

3. Improvement process: increase the diameter of the gate Dummy from 3mm to 4mm. As a result, the cross-sectional area of the gate is increased, the pressure loss is reduced, and the shrinkage problem is solved. Details as the below picture shows.