SHORT-RUN STATISTICAL PROCESS-CONTROL - MULTICRITERIA PART FAMILY FORMATION

Owing to customer demands and short product life cycles, manufacturing trends have shifted towards a wide variety of mixed products with sma ll batch sizes. It is difficult to apply traditional control charts ef ficiently and effectively in such environments, and it is not necessar y 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) over bar control charts are considered simultaneously. This resear ch establishes Shewhart (X) over bar control charts for each part fami ly to examine the quality status of all part types in the same family. We also provide a numerical example for purposes of illustration. (C) 1997 by John Wiley & Sons, Ltd.