Cusum control chart are widely used in process with small shifts. Because of cusum control chart has reasonable detection capability for small shifts. But Cusum control chart has unreasonable detection capability for recurring cycles or quickly change of small shifts. In Shewhart control charts with recurring cycles or quickly change of small shifts, when a point falls outside Shewhart control limits, the process is out of control. But, if assignable causes occur in process and the points falls inside its control limits, process can be considered in-control. For this situations, Shewhart control charts are used zones method ( ex＞ A, B, C ... ). ( We say ‘runs rules’ ) This paper investigated cumulative sum control chart for this some situations.

The traditional control charts have a problem that a control limits are placed to depend on the accuracy of estimate of parameters. This problem caused high false alarm rate. In this paper, we review the uncertainty of control limits and propose the methods which have more reliable control limits using a coefficient of variance. Further more, we present a efficient methods that can control a different type of quality characteristics at the same time. The Weibull distribution is used to modeling the control chart. This type control chart may be useful tools in the short production runs.

We developed the software named as Management Quality Renovation Software in 2002 as a government project supported by the Korean Standards Association. In this paper, we present our ways to help small and medium sized industries improve quality by Management Quality Renovation software.