Purely mechanically, unilateral tolerances are very straight forward for Cpk calculations. But usually, situations calling for unilateral tolerance will also have other peculiarities that make Cpk, SPC and other Six Sigma statistical tools harder to use.

The second part of this video is about a specific example of a unilateral tolerance: the E weight in European food regulations. It stipulates the minimum weight/volume that should be in a consumer unit, and from its tolerance limits we can calculate the optimal standard deviation for our process.