Design for Six Sigma with Critical – To-Quality Metrics for Research Investments

Design for Six Sigma (DFSS) has evolved as a worthy predecessor to the application of Six-Sigma principles to production, process control, and quality. At Lawrence Livermore National Laboratory (LLNL), we are exploring the interrelation of our current research, development, and design safety standards as they would relate to the principles of DFSS and Six-Sigma. We have had success in prioritization of research and design using a quantitative scalar metric for value, so we further explore the use of scalar metrics to represent the outcome of our use of the DFSS process. We use the design of an automotive component as an example of combining DFSS metrics into a scalar decision quantity. We then extend this concept to a high-priority, personnel safety example representing work that is toward the mature end of DFSS, and begins the transition into Six-Sigma for safety assessments in a production process. This latter example and objective involves the balance of research investment, quality control, and system operation and maintenance of high explosive handling at LLNL and related production facilities. Assuring a sufficiently low probability of failure (reaction of a high explosive given an accidental impact) is a Critical-To-Quality (CTQ) component of our weapons and stockpile stewardship operation and cost. Our use of DFSS principles, with quantification and merging of CTQ metrics, provides ways to quantify clear (preliminary) paths forward for both the automotive example and the explosive safety example. The presentation of simple, scalar metrics to quantify the path forward then provides a focal point for qualitative caveats and discussion for inclusion of other metrics besides a single, provocative scalar. In this way, carrying a scalar decision metric along with the DFSS process motivates further discussion and ideas for process improvement from the DFSS into the Six-Sigma phase of the product. We end with an example of how our DFSS-generated scalar metric could be improved given success of our future research investments in impact safety scenarios.