Assemblability evaluation based on tolerance propagation

The specification of tolerances is an integral part of product design since tolerances directly affect the assemblability, as well as the functionality, manufacturability, and cost-effectiveness of the product. However, there has been little research on the assemblability evaluation based on tolerance propagation which can play an important role in assembly planning. Assembly planners in the past have assumed nominal dimensions for product components for generating the feasible assembly sequences. These sequences, however, may not be assemblable in practice due to propagations and accumulations of tolerances. In this paper, we present a new approach to assemblability evaluation based on tolerance propagation. For the assemblability evaluation, we introduce an important concept of clearance. Clearance represents the possible free space between two mating features. In the assemblability evaluation, clearances are used to compensate for tolerances