The development of specifications-based S- and L-type robust designs. (1st January 2013)

• Record Type: Journal Article
• Authors: Chan, Hsin-Li; Cho, Byung Rae
• Is Part Of: International journal of experimental design and process optimisation. Volume 3:Number 4(2013)
• Page Start: 364
• Page End: 383
• Publication Date: 2013-01-01
• Subjects: quality -- S-type -- L-type -- truncated Weibull distribution -- response surface methodology -- RSM -- optimisation; Experimental design -- Periodicals; Process control -- Statistical methods -- Periodicals; 620.0072
• Languages: English
• ISSNs: 2040-2252

Abstract

Chan and Cho (2013) studied the specifications-based robust design optimisation for a nominal-the-best type ( N -type) quality characteristic under the normality assumption as an underlying distribution of the characteristic. In the real life engineering environment, however, various quality characteristics are of smaller-the-better ( S -type) or larger-the-better ( L -type) and their distributions are heavily skewed. As an extension of Chan and Cho (2013), this paper proposes specifications-based robust design (RD) models for S - and L -type quality characteristics, which are constrained by pre-specified upper and lower specification limits (USL and LSL), respectively. This paper demonstrates that the Weibull distribution is effective in modelling the S - and L -type characteristics, derives the truncated mean and variance from the Weibull parameters, and incorporates those truncated statistical moments into response surface-based RD models. Finally, numerical examples illustrate how the optimal factor settings are obtained from the proposed models.