Understanding negative volume shrinkage

Have you ever seen a negative volumetric shrinkage value in Moldflow?

This can happen if the packing pressures are too high. This will force additional material into the part cavity, negating our shrinkage values, and cause the part to expand (compared to the tool cavity). This can also cause sticking issues when the part ejects from the mold.

I think we are all trained to look for high volumetric shrinkage results, but don’t forget to look for negative volumetric shrinkage values as well! And also – look out for the upcoming updates. There may be something to help detect negative volumetric shrinkage.