Simulation of variation for manual assembly when mis-constraining occurs

Abstract

In Computer Aided Tolerancing (CAT) the goal is to virtually predict the variation in critical measures for a product. In order to succeed with that, the simulation model needs to be as accurate as possible, the positioning of the included parts needs to mimic the reality of assembly in production and all the tolerances that influence the results need to be included. For all assembly types, but especially manual assembly, one problem that can occur during assembly is mis-constraining, meaning that the part is positioned but not in the way intended by the designer. This phenomenon leads to quality problems, increased costs, impact on functions, etc. In this paper, the phenomena are illustrated using industrial case studies. Simulation methods to model this are sparse and in this research a new method and simulation tool to include the effects of mis-constraining are proposed and included in a CAT tool.