A Comparative Study of the Monitoring Performance for Weighted Control Charts

Statistical process control (SPC) is the method that monitors process quality characteristic. Through control charts, one can detect whether the present process malfunction. However, some annoyances may arise while the engineers need to choose appropriately control chart under different levels of process malfunction. The main objective of this research is using step-by-step procedures to present a comparative study of the monitoring performance for Shewhart, cumulative sum (CUSUM), exponentially weighted moving average (EWMA) and generally weighted moving average (GWMA) control charts. While the process means or the standard deviations were changing in different levels, the performance of each weighted control chart can be then compared by using average run length (ARL). A rule of thumb for selecting better control schemes is provided as a truthfully reference to help engineers in choosing the more appropriate control charts immediately when the assignable causes occurred.