SHORT-RUN STATISTICAL PROCESS CONTROL: MULTICRITERIA PART FAMILY FORMATION

Abstract

Owing to customer demands and short product life cycles, manufacturing trends have shifted towards a wide variety of mixed products with small batch sizes. It is difficult to apply traditional control charts efficiently and effectively in such environments, and it is not necessary to plot a control chart for each individual part. In this study, we propose a multicriteria part family formation technique and algorithm for implementing short-run SPC charting. We first carry out simulation to obtain ARLs for various shifts, and then use a maximin approach to help obtain a compromise or satisfactory ratio of standard deviations allowable within part families—type I and type II errors of Shewhart X control charts are considered simultaneously. This research establishes Shewhart X control charts for each part family to examine the quality status of all part types in the same family. We also provide a numerical example for purposes of illustration. © 1997 by John Wiley & Sons, Ltd.