Capability Indices Dedicated to the Two Quality Characteristics Case

Abstract

The aim of this paper is to define two new capability indices BC_P and BC_PK dedicated to two quality characteristics, assuming a bivariate normal distribution and a rectangular tolerance region. These new capability indices are based on the computation of the theoretical proportion of non-conforming products over convex polygons. This computation is achieved by a new method of integration based on Green’s formula. The efficiency of the proposed capability indices is demonstrated by comparing our approach with others proposed previously, on simulated and real world industrial examples.

Key Words:

• Bivariate normal distribution
• Green’s formula
• multivariate process capability indices

Additional information

Notes on contributors

Philippe Castagliola

Philippe CASTAGLIOLA He is graduated (PhD 1991) from the UTC (Université de Technologie de Compiègne, France). He is currently professor at the IUT (Institut Universitaire de Technologie) de Nantes, France, and he is also a member of the IRCCyN (Institut de Recherche en Communications et Cybernétique de Nantes), UMR CNRS 6597. He is member of the ASQ and he is also Associate Editor for the Journal of Quality Technology and Quantitative Management. His research activity includes developments of new SPC techniques (non-normal control charts, optimized EWMA type control charts, multivariate capability indices, monitoring of batch processes, …).

José-Victor Garcia Castellanos

José Victor GARCIA-CASTELLANOS. He B.S. in industrial engineering from Instituto Tecnológico de Durango, México. M.S. in industrial engineering from New Mexico State University and Ph.D. in Automatique et Informatique Appliquée, minor in Statistical Methods for Quality, from Ecole des Mines de Nantes, France. Professor at Instituto Tecnológico de Ciudad Juárez in Juarez, Mexico. His research activity includes statistical methods for quality, operation research and simulation. His academic experience includes 23 years at several Mexican universities. He has worked as an industrial consultant in Statistical methods for Six Sigma, Taguchi Methods and Simulation of Manufacturing Systems. He is member of ASQ and INFORMS.