Int. J. Six Sigma and Competitive Advantage, Vol. 1, No. 2, 2005 151 Some thoughts about problem solving in a DMAIC framework Larry R. Smith* Ford Motor Company (retired), 1637 Sherwood Ct. Dearborn, MI 48124-4072 USA E-mail: lrsmith2@peoplepc.com *Corresponding author Madhav S. Phadke Phadke Associates, Inc., 1 Shawnee Court Colts Neck, NJ 07722–1472 USA E-mail: madhav@phadkeassociates.com Abstract: This paper explores the iterative nature of problem solving in the context of a complex system issue involving the interplay of hardware and software on a diesel engine. The case study illustrates how application of TRIZ and parameter design methodologies can greatly enhance and accelerate the problem-solving process. Slow- and high-amplitude oscillation of the entire vehicle powertrain under steady pedal position at idle is called ‘ringing’, and similar behaviour under cruise-control conditions is called ‘hitching’. TRIZ (a Russian acronym for Theory of Inventive Problem Solving) Anticipatory Failure Determination was used to discover root cause. Dr. Taguchi's parameter design was then used to find the appropriate levels for a variety of software variables to virtually eliminate the ‘hitching’ condition. The use of TRIZ and robust engineering methods up-front in the design process, and the distinction between Six Sigma and design for Six Sigma are also discussed. Keywords: DMAIC; problem solving; software control strategy; diesel engine; hitching; TRIZ; anticipatory failure determination; robust design; taguchi; parameter design; design of experiments; dynamic S/N ratio; speed control; vibration control. Reference to this paper should be made as follows: Smith, L.R. and Phadke, M.S. (2005) ‘Some thoughts about problem solving in a DMAIC framework’, Int. J. Six Sigma and Competitive Advantage, Vol. 1, No. 2, pp.151–166. Biographical notes: Larry R. Smith recently ‘graduated’ from a 27-year career at Ford Motor Company, where he held a variety of Quality Management positions, primarily in Vehicle Operations, North American Truck, Powertrain Operations, and Casting Operations. He was instrumental in initiating a Six Sigma effort at Ford Motor Company and acted as deployment champion for the Superduty Truck Platform, whose Six Sigma projects saved $49 million in the first year of operation. A Senior Member and elected National Director of the American Society for Quality for 2004–2005, Smith is the current President of the Altshuller Institute for TRIZ Studies and a Member of the Board of Directors of GOAL/QPC. Copyright © 2005 Inderscience Enterprises Ltd.