A computer-aided tolerance specification method based on multiple attributes decision-making

In the mechanical product design, tolerance specification is a crucial process to select tolerance types to control the geometrical variation of the features on a workpiece. Tolerance specification is a kind of decision-making process which needs to consider many influential factors of the manufacturing cost and quality requirement of a workpiece. In this context, those factors are classified into two categories, that of static factors from the rules and standards, and that of dynamic factors based on the manufacturing site’s information. This paper presents a novel method for computer-aided tolerance specification to evaluate both types of factors while the traditional methods only take the static factors into considerations. Those factors are assessed by the developed MADM (multiple attributes decision-making) algorithm, assisted with the rule-based algorithm and axiomatic design algorithm. A case study is undertaken, and its result shows the effect of dynamic factors on the output of tolerance specification. The results adhere to the ISO standard.