Preface

The success of the Six Sigma movement has generated enormous interest in business world. By quoting one of our friends, Subir Chowdhury, “people’s power” and “process power ” are among the keys for the success of Six Sigma. The people’s power means systematic organization support led from the top, and rigorous training for Six Sigma team members. The process power means the rigor of Six Sigma deployment and project management processes, and a wide array of statistically based methods. It is our belief that unlike other quality improvement movements, where the focus is primarily on the quality of the product r service to external customers, Six Sigma is focusing on the whole quality of a business enterprise. The whole quality includes not only the product or service quality to external customers, but also the operation quality of all internal business processes, such as accounting, billing, and so on. The business enterprises that have high levels of whole quality will not only provide high quality product or services, but also they will have much lower cost and high efficiency because all their business processes are optimized. Compared with the “regular” Six Sigma that is featured by “DMAIC” (define-measure-analysis-improve-control), the new wave of Six Sigma is called Design for Six Sigma (DFSS). The regular Six Sigma is also called Six Sigma improvement, that is to improve a process without design or completely redesign the current system. Design for Six Sigma puts a lot of focus on design and it tries to “do things right at the first time.” In our understanding, the ultimate goal of DFSS is to make a process or a product to: (1) Do the right things; and (2) Do things right all the time. Do the right things means achieving absolute excellence in design, be it in designing a product, a manufacturing process, a service process or a business process. Superior product design will deliver superior products that deliver right product functions to generate great customer excitement. Superior manufacturing process design will generate a process that delivers the product in a most efficient, economic, and flexible manner. Superior service process design will generate a process that fits customer desires and provides service with quality and low cost. Superior business process design will generate the most efficient, effective, and economical business process.

Do the right thing all the time means that not only should we have superior design, but the actual product or process that we build according to our design, will always deliver what it is supposed to do. For example, if a company can develop some very superior products sometimes, but it also develops some poor products, then this company does not do the right thing all the time . If people buy cars from a world-class brand-name, they really expect all the cars from that brand-name to perform well and that these cars will perform consistently during their useful life; that is what we mean by ‘do things right all the time’. Do things right all the time means high consistency and extremely low variation in performance. The term Six Sigma actually means very high consistency and low variation. Nowadays, high consistency is not only necessary for product performance and reputation; it is also a matter of survival. For example, the dispute between Ford and Firestone tires only involves an extremely small fraction of tires, but the negative publicity and litigation brought a giant company like Ford into an unpleasant experience. Implementing DFSS, as previously stated, will involve (1) doing the right things and (2) doing things right all the time by using “people’s power” and “process power.” The people’s power involves organizational leadership and support, as well as a tremendous amount of training. The process power envolves a sophisticated implementation process and a big collection of methods. Compared to regular Six Sigma (DMAIC), many new methods are introduced in DFSS. Examples are axiomatic design, design for X, and theory of inventive problem solving (TRIZ). Transfer functions and scorecards are really powerful concepts and methods to create superior designs, that is, to do the right things. DFSS also brings another class of powerful methods, Taguchi’s methods, into its tool box. The fundamental objective of the Taguchi methods is to create a superior product or process that can perform highly consistently despite many external disturbances and uncertainties. In other words, Taguchi methods create a robust product or process, thus achieving do things right all the time. The implementation of DFSS will take more effort and training than that of DMAIC, but it will be more rewarding and provide better results.