Computer aided assembly robustness evaluation

Abstract

This paper presents a methodology and a software that allows assemblies to be evaluated with respect to robustness and geometrical stability. The assembly robustness evaluation aims at detecting design and assembly solutions that are sensitive to variation and may cause problems later during production. It is based on Suh's independence axiom, stating that in a good, uncoupled design, each functional requirement is satisfied by one and only one design parameter. The methodology enables the designer to evaluate the geometrical sensitivity of the assembly, what the sources of variation are, their importance for the overall robustness and in what order to improve the design. A possible result from the analysis may be that the concept must be changed in some way, either by changing the way parts are located with respect to each other or by using assembly fixtures for positioning. The software is implemented in a Microsoft Windows environment and has an IGES interface that enables the designer to import computer aided design (CAD) geometry from an arbitrary CAD system, and perform assembly robustness analysis.