A proposed procedure for variable sampling plans design based on process capability index

Muhammad Aslam, Chien-Wei Wu, Muhammad Azam, Chi-Hyuck Jun


The article presents the tightened-normal-tightened acceptance sampling plan using the process capability index Cpk. The plan parameters of the proposed plan are obtained by solving an optimization problem such that the producer’s risk and the consumer’s risk are satisfied simultaneously for several specified combinations of acceptable quality level and limiting quality level. The plan parameters are tabulated and discussed for the industrial use when the fractions non-conforming beyond the lower and the upper specification limits are symmetric or asymmetric. We illustrate the proposed plan with the help of a real example. We compare the efficiency of the proposed plan with the existing sampling plans.

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