Economic specification limits and process mean settings by considering unequal target value and specification center

In this paper, the author proposes a modified Kapur and Wang's model with unequal target value and specification center. The economic specification limits and process mean are determined by minimizing the expected total quality loss per unit product under the specified process capability index value. The process capability indices Cpm and Cpmk correlated with Taguchi's quadratic quality loss function are considered. The 100% inspection is executed before the product shipped to the customer. Taguchi's asymmetric quadratic quality loss function is applied in evaluating the product quality. The numerical results show that the modified model with specified Cpm value has smaller specification tolerance, larger process mean, and smaller expected total cost per unit product than those of the modified model with specified Cpmk value.