Critical dimensions are those dimensions where the part specifications demand that the indicated tolerances be met.
Starting a shrinkage suggestion analysis triggers the calculation of a recommended dimensional shrinkage allowance to use when designing the mold. The calculation takes into account the shrinking characteristics data of the current material as obtained from shrinkage testing. If shrinkage characteristics data is not available, the calculation is based on material properties that are available, resulting in a close estimate.
The part designer can use the following information in the Summary dialog to meet the required tolerances for the critical dimensions:
The original part dimensions specified by the part designer, which never change.
The percentage increase applied to the part dimensions to generate the mold cavity dimensions.
The actual size of the cavity cut in the mold. Cavity Dimensions = Nominal Dimensions * (1 + Shrinkage Allowance).
The estimated amount of shrinkage, generated by analysis, based upon the mold cavity dimensions. This value is expressed as a percentage.
The estimated final part dimensions, produced by the Shrinkage analysis. This estimate is equivalent to Mold Cavity Dimensions - Estimated Shrinkage.