Shrinkage is a reduction in the dimensions of a plastic part compared with the mold dimensions. Variations in shrinkage within the part cause warp issues.
Select Compensate for Shrinkage to make the mold cavity size larger than the part design size to compensate for the expected material shrinkage.
By default, the material shrinkage factor from the material database is used as a shrinkage allowance. You can find it in the Material Properties dialog, Shrinkage tab, Average Nominal Shrinkage box. You can also enter your allowance value.
Average Nominal Shrinkage represents the average shrinkage value observed during shrinkage testing, which depends on many factors including material structure. For example, crystalline materials have a greater tendency to shrink than amorphous materials. If the material has not been shrinkage tested, the data may be a single value for shrinkage set by the ISO standards.