Title: Some thoughts about problem solving in a DMAIC framework

Authors: Larry R. Smith, Madhav S. Phadke

Addresses: Ford Motor Company (retired), 1637 Sherwood Ct., Dearborn, MI 48124-4072, USA. ' Phadke Associates, Inc., 1 Shawnee Court, Colts Neck, NJ 07722–1472, USA

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 engines; hitching; TRIZ; anticipatory failure determination; robust design; Taguchi methods; parameter design; design of experiments; dynamic S/N ratio; speed control; vibration control; six sigma quality; design for six sigma; quality improvement.

DOI: 10.1504/IJSSCA.2005.006428

International Journal of Six Sigma and Competitive Advantage, 2005 Vol.1 No.2, pp.151 - 166

Published online: 07 Mar 2005 *

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