Lower confidence bound for capability indices with one-sided tolerance processes and measurement errors. (19th October 2011)

• Record Type: Journal Article
• Authors: Grau, Daniel
• Is Part Of: International journal of quality engineering and technology. Volume 2:Number 4(2011)
• Page Start: 291
• Page End: 305
• Publication Date: 2011-10-19
• Subjects: quality technology -- process capability indices -- gauge measurement error -- one-sided tolerance process -- lower confidence bound; Engineering -- Quality control -- Periodicals; Systems engineering -- Periodicals; 620.0045
• Languages: English
• ISSNs: 1757-2177

Abstract

The families of process capability indices Cp u ( u, v ) and Cp l ( u, v ) provide measurements of process performance for one-sided processes. In this work we deal with the problem of gauge measurement errors effects on the performance of these indices. We show that using a lower confidence bound without taking these errors into account, severely underestimates the true capability. In order to improve the results, we suggest using an adjusted lower confidence bound, and we give a Maple program to obtain this bound. We finally present a real study on a polymer granulates manufacturing process to illustrate how to make use of our suggestion.