Method of improving the design quality of products by elaborating Robust Design within an AD framework

The overall quality level of a product can be improved by using Robust Design methodology. The objective of this methodology is to reduce the variance of the response, thereby making the system less sensitive to the variation of casual factors associated with it. Sensitivity can be reduced by an appropriate choice of the values assigned to the control factors of the product. Axiomatic Design, on the other hand, is a methodology that guarantees an innovative approach to design. The design is represented as a set of Functional Requirements which Axiomatic Design has to carry out and the appropriate Design Parameters for satisfying these Functional Requirements. The interaction between the Functional Requirements and the Design Parameters is represented by means of a matrix called the Design Matrix: each function is broken down and the process is repeated until a hierarchy of Design Matrices has been established. The decision as to which design is the best is entrusted to two axioms. The purpose of this paper is to highlight the connections between these two design methodologies and their similarities, as well as indicating how their combined use simplifies their common task of obtaining a more robust, and so with a better quality level, design. It is, in fact, possible to link the first Axiomatic Design axiom to the Concept phase and the second axiom to the Parameter and Tolerance phases. A simple example is provided to illustrate how this integration works.