Statistical tolerance and clearance analysis for assembly

In this paper, we present statistical tolerance and clearance analysis for the assembly. Tolerances work against the assemblability of a product since they can propagate and accumulate in the product, making it more difficult or impossible to assemble. Clearances work for the assemblability since they can be used to compensate for tolerances. The poses of parts in an assemble may be adjusted within the permitted clearances to assemble the parts. Monte-Carlo method is used in the analysis, with Gaussian distribution, Gaussian-Sigmoid distribution, and Chi-Square error reduction scheme to approximate tolerances and clearances. Then, algorithms to compute the propagation of tolerances and clearances are proposed. Our proposed work is expected to make the following contributions: 1) to help the designers to evaluate products for assemblability, 2) to provide a new perspective to tolerance problems, and 3) to provide a tolerance analysis tool which can be incorporated into a CAD or solid modeling system