There is obviously the classic dictionary type definition such as: Design for Six Sigma (DfSS) is an emerging business process which involves a highly disciplined methodical approach to integrating the principles of Six Sigma as early as possible into the design and development process. It is a customer-driven business strategy that creates robust designs that have Six Sigma Quality “Designed In” to meet customer defined critical-to-quality (CTQ) requirements. DfSS is an evolutionary process that promotes cultural change by transforming a company’s vision to move from a reactive “problem solving” to a predictive “problem prevention” organization.

DfSS can be used for:

  • Designing and developing a new design with predictable functional performance
  • Implementing major changes to an existing design when variation associated with continuous improvement efforts have reached a point of diminishing returns and an innovative redesign effort is required
  • Indicated by system-wide changes
  • Reducing common cause variation
  • Achieving quantum “breakthrough” design improvements

Historically, DfSS evolved in part because Six Sigma organizations found that with some designs they could not optimize them beyond three or four Sigma without fundamentally having to redesign the product, process or service. By implementing a DfSS strategy to more fully understand customer requirements, ‘Six Sigma’ levels of performance can be “designed-in” from a very early design conception stage within their design and development process. Many companies consider DfSS to fall under the general umbrella of Six Sigma. It is often seen that the tools used for DfSS can encompass methodologies in addition to those used for DMAIC Six Sigma such as Systems Engineering, Robust Design, Reliability Engineering, Innovation techniques and Quality Function Deployment (QFD) to capture Voice of Customer (VOC) critical-to-quality (CTQ) requirements.

But what is the real definition of DfSS? My experience has taught me that there is no single definition for DfSS. It is a discipline that any organization that is in the business of creating designs which exceed customer requirements to maintain unwavering customer loyalty, needs to uniquely define for their particular business. DfSS aspires to create an innovative design solution with the end user in mind by optimally building the efficiencies of Six Sigma methodology into the design or process before commercialization; where as traditional Six Sigma seeks for continuous improvement after a design or process already exist. A DfSS program deployment should be customized for whatever a company “designs”, the multiple customer applications that a design can be used for, and the industry the company is associated with. Once a DFSS roadmap is defined for an organization, it becomes more powerful when it is integrated into the company’s design and development process framework. Since DfSS drives the future designs that are used by their specific customers, it can be thought of as means for enduring sustainability of a business when well executed.

DfSS should not be considered a one-size-fits-all business strategy and is not necessarily a discipline that is deployed to the masses within a company. This is evidenced by the fact that many DfSS process models exist such as DMADV, IDDOV, IDOV, etc. to name a few; whereas DMAIC remains a standard process model for Six Sigma.

How the automotive industry defines their DfSS process and associated tool set may be quite different from other industries such as healthcare, food, consumer goods, chemical, energy management, banking or medical devices. Why so many process models you may ask – because what they design and the customers they design for are unique to the business they reside in. In addition to DfSS being a powerful toolset, it is a business strategy that an organization should consider to be a longer term investment of resources than Lean or Six Sigma, before improvements in customer satisfaction are realized. DfSS is an evolutionary journey which requires refinement over time by applying the techniques to many different types of “design” projects before the true definition of its success is realized by that organization, and becomes engrained into the company’s culture as the way that they deliver robust designs to their customers.

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