Axiomatic Design Theory is one of the most useful design methodologies which uses Functional Requirements(FRs) and Design Parameters(DPs) to make human designers more creative, to reduce the random search process, to minimize the iterative trial-and-error process, and to determine the best design among those proposed. In this research, we show how to develop a CAD system for an automotive rubber machinery using the axiomatic design approach to illustrate the effectiveness of the theory and we suggest a better way to select FRs and DPs in axiomatic design approach which can help designers to select them more effectively, objectively, and easily.