Often times when we hear that there is a random filling imbalance related to a random part quality issue, we are skeptical that the problem is truly “random”. A majority of molds that we are asked to look at often times have a pattern to the data, and therefore, a common root cause behind the associated problems. These patterns may be a result of either non-uniform shear heating variations or steel related issues that affect a certain set of cavities. In order to first determine if there is a pattern, we need to break down a mold into flow groups and regions. By determining flow groups in a mold, not only can a person more easily find the true imbalance but it is also easier to determine the source(s) of the imbalances.