Optimum process mean setting with specified average outgoing quality limit protection for variable single sampling plan

Abstract

The average outgoing quality limit (AOQL) is a major performance evaluation for assuring the quality of product lot. The process mean setting is an important topic for statistical process control. In this paper, the author applies a variable single sampling inspection plan with the AOQL protection on the consumer for determining the optimal process mean and the parameters of sampling plan. The quality characteristic is considered with one-side lower specification limit and it is normally distributed with known standard deviation and unknown mean. The 100% inspection is adopted when the product lot is rejected. The optimum process mean and parameters of inspection plan are simultaneously determined by maximizing the expected total profit per unit under the specified AOQL value. The numerical example and sensitivity analysis of parameters are provided for illustration.