Modeling Variation in Multi-station Compliant Assembly using Parametric Space Envelope

Non-rigid compliant parts are widely used in industries today. One of the biggest challenges facing the industries is geometric variation management of these compliant parts, which directly impacts product quality and functionality. Existing rigid body based variation modeling is not suitable for compliant assembly while finite element analysis based methods have the disadvantage of requiring heavy computation efforts. In view of that, this paper develops a novel methodology to evaluate geometric variation propagation in multi-station compliant assembly based upon parametric space envelope (i.e. variation tool constructed from parametric curves). Three sources of variation: location-led positional variation, assembly deformation-induced variation and station transition caused variation are analyzed. Under proposal, geometric variations are modeled indirectly through a compact set of boundary control points. Compared with existing methods where geometric variation is modeled through targeting key feature points on the manufacturing part, the proposed approach brings modeling accuracy and computation efficiency. The effectiveness of the method is illustrated and verified through an industrial case study on a multi-station compliant panel assembly. The developed method provides industries a new way to manage geometric variation from compliant assembly.