ABSTRACT
Traditional tolerancing research [1,2] mainly focused on an assembly that is built up through many mating features of individual components. Raw parts are inherently imprecise; tolerance is used to control the quality of the final product by specifying allowable limits on raw parts. There are two basic directions in tolerancing research: (1) tolerance analysis or (variation) prediction, and (2) tolerance synthesis or allocation. Tolerance analysis predicts the variation of the final product given the tolerance of each part. The basic idea of tolerance analysis is represented in Figure 15.1. First, a mathematical expression, such as geometrical or dimensional tolerance, is used to represent the raw part tolerance according to their properties. Then, based on mathematical model of tolerance accumulation, such as the worst case (WC) model and root square sum (RSS) model [3,4], the final product variation as an accumulation of part tolerance is computed and predicted.
