Manufacturing capability control for multiple power-distribution switch processes based on modified C-pk MPPAC

Abstract

A modification of the multiple process performance analysis chart based on process capability index C-pk, called modified C-pk MPPAC, has been developed for controlling product quality/reliability of a group of multiple manufacturing processes. The modified C-pk MPPAC conveys critical information of each individual process regarding process accuracy and process precision from one single chart, which is an effective tool for controlling product quality/reliability for multiple processes. Existing MPPAC charts never considered sampling errors hence the capability information provided from those charts is often unreliable and misleading. In this paper, we develop an efficient algorithm to compute the lower confidence bounds of C-pk. The lower confidence bound presents the minimum true capability of the process, which is essential to product reliability assurance. We apply the lower confidence bounds to the modified C-pk MPPAC to provide reliable simultaneous capability control for multiple processes. A case involving multiple processes manufacturing power-distribution switch (PDS) is investigated. The modified C-pk MPPAC incorporating with the lower confidence bound is applied to the capability control of multiple PDS processes. (C) 2003 Elsevier Science Ltd. All rights reserved.