Economic design of x-bar control chart under hybrid maintenance policy

Purpose According to the relevance of product quality and machine degradation state, a hybrid maintenance policy is designed. The paper aims to discuss this issue. Design/methodology/approach Product quality control and machine maintenance are considered simultaneously in this policy. Based on this policy, the economic model of x-bar control chart is proposed using statistical process control and renewal reward theory. Findings This model is solved by genetic algorithm and the experimental results validated its feasibility. Originality/value In this model, the four corresponding relationship, which is between product quality monitoring result and machine degradation state, is analyzed.