Economical operation of the C pm control chart for monitoring process capability index

Maiko Morita, Ikuo Arizono, Ippei Nakase, Yasuhiko Takemoto

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Process capability indices are widely used to provide the evaluation measure of a process. Especially, the process capability index Cpm , which is defined by the range of the process standard specification limits and the deviation from a target value, is called the Taguchi index. Boyles has investigated the statistical characteristics of the estimator Ĉpm and also proposed a technique for the Cpm control chart. Since the process capability index Cpm is based on the concept of the Taguchi's quality loss, the process capability index C pm already includes an economical concept. In this article, we evaluate an operating cost consisting of the sampling cost, the sample cost, and the quality loss of failing to detect an out-of-control state when the C pm control chart is used. Then, we derive an optimal operating plan by sample size and sampling interval in order to minimize the ceiling value of the operating cost based on the min-max criterion.

Original languageEnglish
Pages (from-to)304-311
Number of pages8
JournalInternational Journal of Advanced Manufacturing Technology
Volume43
Issue number3-4
DOIs
Publication statusPublished - Jul 2009
Externally publishedYes

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Keywords

  • Ccontrol chart
  • Maximum likelihood method
  • Min-max criterion
  • Patnaik's approximation
  • Process capability index C
  • Taguchi's loss function

ASJC Scopus subject areas

  • Industrial and Manufacturing Engineering
  • Control and Systems Engineering
  • Computer Science Applications
  • Software
  • Mechanical Engineering

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