Economic design of double sampling C_pm control chart for monitoring process capability

In this papers, we address a double samplimg C_pm control chart. It is well known that a double sampling scheme can reduce average sampling number in comparison with a single sampling scheme in sampling inspection. However, it is complicated and difficult to design the double sampling C_pm control chart because a judgment rule of the 2nd sampling stage depends on a record of 1st sampling stage. Therefore, this paper proposes a double sampling C_pm control chart incorporating the feature that a judgment rule of 2nd sampling stage is independent of a record of 1st sampling. The design algorithm for the proposed double sampling C_pm control chart is constructed by taking the economical operation of this control chart into the consideration. That is, the economic design of the double sampling C_pm control chart is addressed. Through some numerical comparison, it has been confirmed that the proposed double sampling C_pm control chart has an advantage in the expected total operating cost over the traditional single sampling C_pm control chart.