A spatial multivariate process capability index

Process capability ultimately decides process quality level. Based on analyzing process capability index (PCI), Process capability may be effectively assured. For the multivariate manufacturing processes, tremendous difficulties are often encountered when one attempts to measure the process capability by directly extending the univariate approach. After analyzing the multivariate Cpm method (Chan et al. 1991), the paper presents a spatial multivariate PCI method, which can solve multivariate off-centered case and may provide references for assuring and improving process quality level while achieving overall evaluation of process quality. At last, examples for calculating multivariate PCI are given and the experimental results show that the systematic method presented is effective and actual.