Designing quality into products and processes

•Product design is the prime activity in the process of realizing a product. Therefore it has the greatest impact on the product quality. Loss of quality occurs when there is a deviation of functional characteristics of the products from the target values.

•Taguchi has proposed a philosophy and methodology for designing quality into products and processes. He postulates that the process of designing a product or a process should be viewed as three phases.

•System Design, Parameter Design and Tolerance Design

What is system design ?

System design is the process of applying scientific knowledge to produce a basic functional prototype design. In this phase, new concepts, ideas and methods are synthesized to provide new or improved products to customers. That means that the basic design concept is established during this phase including selection of parts, materials and sub-assemblies.

What is parameter design ?

In the parameter design phase, the levels for the products/ process design parameters are set to make the system performance less sensitive to causes of variation thus minimizing quality loss.

What is tolerance design ?

The tolerance design phase usually follows the parameter design phase. Quality improvement is achieved by tight tolerances around the chosen target values of the control factors so as to reduce performance variations.

Source:NPTEL