The integrated study for process improvement with economic specification limits, process means setting and quality investment: an extension of the model in Abdul-Kader et al. (2010)

Abstract

ABSTRACT In the present paper, the model in Abdul-Kader et al is modified by incorporating the capability index Cpm to assure the capability of production process and to obtain the process mean, economic specification limits, and quality investment level with minimization of the expected total cost per item. Three modified models are presented and discussed, where Model I firstly determines the optimal process mean and economic specification limits, and then by applying this optimal mean and specification limits, the optimal quality investment level is subsequently obtained, Model II firstly determines the optimal process mean and quality investment level and then, by applying this optimal mean and quality investment level, the economic specification limits are obtained afterwards, and Model III simultaneously determines the optimal process mean, economic specification limits and the optimal quality investment level. Solution procedure for each modified model is provided and a numerical example is given for illustration. Based on the results of sensitivity analysis, Model II is generally superior to the other two modified models under consideration of cost.