A Feature-Based Tolerancing Model for Functional Analysis in Assemblies of Rigid Parts

In the real assembly processes, due to the lack of tools and methodologies for checking assembly and functional requirements, many fit-up problems of parts or sub-assemblies can occur when trying to put components together. Analyzing the different sources of variations, such as those coming from wrong part fabrication, is the right way to prevent and control fit-up problems. To model and control the allowable small variations, a fea-ture-based tolerancing model is proposed for analyzing the relative position of rigid parts in assembly, and variations of assembly features. Matrix transformations are used to locate features and represent the small displacements due to feature tolerances. The proposed model will be analyzed from a functional point of view to check out if functional requirements can be defined and delivered through tolerancing parameters in the tolerance analysis and synthesis phases.