A new multiple dependent state sampling plan based on one-sided process capability indices

Process capability indices (PCIs) are effective quality tools for evaluating process performance in the manufacturing industry. Over a period of more than 15 years, sampling plans based on PCIs have been developed for lot sentencing. Sampling plans that involve repetitive sampling or multiple dependent (deferred) state sampling achieve significant sample size reductions relative to sampling plans that involve single sampling. In this study, we combine the concepts of repetitive and multiple dependent state sampling to propose a new variable sampling plan based on one-sided PCIs. The proposed sampling plan minimizes the average sample number while satisfying the principle of two points on the operating characteristic curve. To demonstrate the performance of the proposed sampling plan, a comparison with existing homogeneous sampling plans is performed.