Reducing warpage due to differential shrinkage

There are several ways to alter differential shrinkage.

The main ways of influencing differential shrinkage effects are:

• Designing packing profiles.

• Reducing part thickness variations.

Note: If you have previously reduced orientation effects, the differential shrinkage effects may be quite different to those found in the original part model because of changes to gate locations, or part thickness etc. Thus you must repeat the full Fill+Pack, Cool, Packing and Warpage analyses for the part model.

Use a packing profile

The first option to consider when reducing differential shrinkage is the use of a packing profile-this of course is dependent on the machine response time and its effectiveness may be limited for thin parts or parts with complex geometries.

Note: The advantage of using a packing profile to reduce warpage is that this does not involve changing the design specifications of the part.

If you decide to use a packing profile to reduce the differential shrinkage in a part, you must repeat the full Fill+Pack, Cool, Packing and Warpage analyses for the part model with reduced orientation levels.

Reduce part thickness variations

If you decide that changes to the wall thickness may be of more use in reducing differential shrinkage effects for the part, then you can proceed to alter the thickness in the region in question and re-analyze the modified part model. This can be an iterative process, until the differential shrinkage level is acceptable.