Statistical Tolerance Stackups

Statistical Tolerance Stackups determine the probable or likely maximum variation

possible for a selected dimension. Similar to worst-case Tolerance Stackups, all

tolerances are added to obtain the total variation. This method, however, more

realistically assumes that it is highly improbable that all the dimensions in the Tolerance

Stackup will be at their worst-case low limit or high limit at the same time. Remember,

the worst-case Tolerance Stackup result requires some dimensions to be at their low limit

and others to be at their high limit. So the direction of the deviation as well as the amount

of deviation must be just so to achieve a worst-case condition.