Evaluating the manufacturability of machined parts and their setup plans

Design-for-manufacturability is an approach that requires product designers to consider the manufacturing issues of a product concurrently with the geometrical and design aspects. This paper presents a manufacturability evaluation methodology that incorporates design, machining and work-holding issues. The evaluation is carried out in two parts. The first part is related to the machinability of the features of the part, whereas the second part is concerned about the fixturability of the part with regards to its planar faces. The methodology uses the fuzzy sets theory and the analytical hierarchy process method to evaluate the accessibility, orientation, dimensional tolerances, and surface finish specifications of a part. The former is used to model the various ill-defined boundaries of the criteria, while the latter allows for differences in opinions from designers/machinists to be incorporated into the evaluation process. The quantitative machinability and fixturability indices found can be used to evaluate designs and generate redesign suggestions. A setup plans evaluation module has been developed to determine the merit indices of setup plans for machining a part using these machinability and fixturability indices.