An Economic design for a variable-sampling-interval {\bar{x}} control chart for a continuous-flow process

Most of the studies in economic design of control charts focus on a fixed-sampling interval (FSI), however, it has been discovered that variable-sampling-interval (VSI) control charts are substantially quicker in detecting shifts in the process than FSI control charts due to a higher frequency in the sampling rate when a sample statistic shows some indication of a process change. In this paper, an economic design for a VSI $\bar{x}$ control chart is proposed for a continuous-flow production process. The results of a numerical example adopted from an actual case indicate that the economic design of VSI control charts is consistently lower in loss-cost than that of the FSI scheme.