Designing-in of quality through axiomatic design

Decisions made during the design stage of product and process development profoundly affect product quality and process productivity. To aid in design decision making, a theoretical framework is advanced; the axiomatic approach to design. Axiomatic design consists of: (1) domains in the design world; (2) mapping between these domains; (3) characterization of a design by a vector in each domain; (4) decomposition of the characteristic vectors into hierarchies through a process of zigzagging between the domains; and (5) the design axioms, viz, independence and information axioms. Statistical process control (SPC) and other methodologies to improve quality are valid only when they are consistent with the independence and information axioms. This paper presents several criteria that govern the design and manufacture of quality products. To be able to control the quality of products, a design must satisfy the independence axiom. Based on this axiom and some theorems, several design criteria are derived and discussed. These criteria provide the bounds for the validity of some of the SPC techniques being used. When there is more than one acceptable design of a product or process, the information axiom must be used to select the best design(s)