ISSN: 1945-7553
CODEN: JTEVAB
Published Online: 1 March 2012
Page Count: 7

An Effective Procedure for Calculating Weibull Production Yield with Mean Shift

Hsu, Ya-Chen
Dept. of Business Administration, Yuanpei Univ., Hsinchu,

Pearn, W. L.
Dept. of Industrial Engineering and Management, National Chiao Tung Univ., Hsinchu,

Li, Yuan-Yi
Dept. of Industrial Engineering and Management, National Chiao Tung Univ., Hsinchu,

(Received 4 January 2011; accepted 21 November 2011)

Abstract

Motorola, Inc. introduced its six sigma production quality initiative to the world in the 1980 s. Six sigma production quality is estimated by assuming a 1.5σ shift to the process mean. Bothe provided a statistical reason for considering such a shift in the normal process mean, and he also provided a much more accurate capability calculation to measure the production yield (Bothe, D. R., “Statistical Reason for the 1.5σ Shift,” Qual. Eng., Vol. 14(3), 2002, pp. 479–487). In this paper, we consider Weibull processes, which cover a wide class of non-normal processes. We calculate the mean shift adjustments under various sample sizes n and Weibull parameters, with the power fixed at 0.5. Then, we implement the derived results to develop an effective procedure to accurately calculate the production yield. Finally, to demonstrate the applicability of the proposed approach, the proposed procedure is applied to a real manufacturing process with mean shift.

Keywords:
production yield, non-normal, Weibull distribution, mean shift, process capability index

Paper ID: JTE103728
DOI: 10.1520/JTE103728
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