Taxonomy of models for tolerance analysis in assembling

The dimensional and geometrical variations of each part have to be limited by tolerances in order to guarantee quality and, in the same time, a decrease of the manufacturing costs. Therefore, how to allocate the tolerances among the different parts of an assembly is the fundamental tool to ensure assemblies that work rightly at lower costs. Tolerance analysis allows to evaluate the cumulative effect that the single tolerances assigned on the components has to satisfy the functional requirements of the whole assembly. The results of the tolerance analysis are meaningfully conditioned by the adopted mathematical model. The purpose of this work is to analyse the most significant models for tolerance analysis. The first part of the paper describes a description of the most common criteria used to categorize existing models for tolerance analysis. A taxonomy is then suggested that may be a useful tool to help evaluate, compare and select such models. Five of the most representative models are explained and discussed in detail in order to identify their strong points and their limitations.