Monitoring product quality in cliching process: comparison between univariate and multivariate control charts

In this dissertation, we investigate the stability of clinching process for assembly of LED Lamps II. Currently, univariate control charts such as X chart and R chart are develop for monitoring process target and process variability. However, the company management under study is highlighting the issue of quality in a clinching process because univariate control charts allow only monitoring one quality characteritic at a time. In multivariate environment, there are more than one quality characteristics to be monitored and those characteristics are correlated.