Taguchi Methods

from the Perspective of Competitive Advantage

by
Edwin B. Dean

The true power of Taguchi methods comes from their simplicity of implementation. They are often applied on the Japanese manufacturing floor by the technicians to improve their product and their processes. The goal is not just to optimize an arbitrary objective function, as they are so often used in the USA. The goal is to reduce the sensitivity of engineering designs to uncontrollable factors or noise. The objective function used is the signal to noise ratio which is maximized. This moves design targets toward the middle of the design space so that external variation effects the behavior of the design as little as possible. This permits large reductions in both part and assembly tolerances which are major drivers of manufacturing cost. Linking quality characteristics to cost through the Taguchi loss function (Taguch and Yokoyama, 1994) was a major advance in quality engineering, as well as in the ability to design for cost.

Taguchi methods are claimed to have provided as much as 80% of Japanese quality gains. This is no small feat considering that Japanese quality gains have brought a large number of industries in the USA to their knees (Dertouzos, Lester, and Solow, 1989).

Taguchi methods are also called robust design in the U.S.A (Phadke, 1989).

Nair (1992) provides many perspectives of Taguchi's parameter design.

A full understanding of Taguchi methods requires reading Taguchi (1987). However, the beginner should start with Peace (1993) and follow that with either Taguchi (1986) or Phadke (1989). Another good choice is to read Fowlkes and Creveling (1995). Taguchi and Yokoyama (1994) provides a throrough coverage by the master in the style of a typical western design of experiments text. Song, Mathur, and Pattipati (1995) provides a notable extension of robust design into the realm of multicriteria optimization.

References

• Dertouzos, M. L., R. S. Lester, and R. M. Solow (1989). Made in America: Regaining the Productive Edge, HarperPerennial, New York NY.
• Fowlkes, W. Y. and C. M. Creveling (1995). Engineering Methods for Robust Product Design: Using Taguchi Methods in Technology and Product Development, Addison-Wesley Publishing Company, Reading MA.
• Nair, V. N., ed. (1992). "Taguchi's Parameter Design: A Panel Discussion," Technometrics, Vol. 34, No. 2, May, pp. 127-161.
• Peace, G. S. (1993). Taguchi Methods: A Hands-On Approach, Addison-Wesley Publishing Company, Reading MA.
• Phadke, M. S. (1989). Quality Engineering Using Robust Design, Prentice Hall, Englewood Cliffs NJ.
• Song, A. A., A. Mathur, and K. R. Pattipati (1995). "Design of Process Parameters Using Robust Design Techniques and Multiple Criteria Optimization," IEEE Transactions on Systems, Man, and Cybernetics, Vol. 25, No. 11, November.
• Taguchi, G. (1986). Introduction to Quality Engineering: Designing Quality into Products and Processes, Asian Productivity Organization, available in the USA from American Supplier Institute, Dearborn MI.
• Taguchi, G. (1987). System of Experimental Design: Engineering Methods to Optimize Quality and Minimize Costs, Vols. 1 & 2, UNIPUB/Kraus International Publications, White Plains NY.
• Taguchi, G. and Y. Yokoyama (1994). Taguchi Methods: Design of Experiments, American Supplier Institute, Dearborn MI, in conjunction with the Japanese Standards Association, Tokyo, Japan.

Bibliographies

Taguchi Methods Bibliography

Taguchi Loss Function

Taguchi Methods at Linköping University

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