Title: Lower confidence bound for capability indices with one-sided tolerance processes and measurement errors

Authors: Daniel Grau

Addresses: Laboratory of Applied Mathematics, CNRS UMR 5142, IUT de Bayonne, Université de Pau et des Pays de l'Adour, 17 Place Paul Bert, 64100 Bayonne, France

Abstract: The families of process capability indices C_p^u (u, v) and C_p^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.

Keywords: quality technology; process capability indices; gauge measurement errors; one-sided tolerance processes; lower confidence bound; polymer granulates manufacturing.

DOI: 10.1504/IJQET.2011.043169

International Journal of Quality Engineering and Technology, 2011 Vol.2 No.4, pp.291 - 305

Published online: 21 Feb 2015 *

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