Casting Process Selection using AHP and Fuzzy Logic

Given the requirements of a product, selecting the most suitable casting process is a multi-criteria decisionmaking problem. A number of casting processes are available today, and these differ greatly in terms of capabilities, advantages and limitations in relation to design (example: geometry), quality (ex. tolerance), production (ex. lead time) and cost (ex. labor). These characteristics vary with the type of cast metal, leading to a large number of material dependent process-characteristics. This paper presents a systematic approach for evaluating product-process compatibility, which is useful for casting process selection and product design improvement. Nineteen criteria (critical, objective and subjective type) have been identified to evaluate the suitability of a casting process for the given design. The criteria are assessed using linear weighing and fuzzy logic models, and their relative importance is determined using Analytical Hierarchy Process, to finally arrive at the product-process compatibility index. A sample database of process characteristics has been created and a case study is presented to demonstrate the approach.