Joint modeling of preventive maintenance and quality improvement for deteriorating single-machine manufacturing systems

For a deteriorating single-machine manufacturing system, preventive maintenance (PM) is an effective way to improve the machine reliability and product quality. In conventional PM models, however, quality improvement has been seldom considered, which may lead to loss of economic benefits. In this paper, a joint model is proposed, in which quality improvement is integrated into PM decision-making. In the proposed model, process variables affecting product quality are identified, among which adjustable process variables are measures of the degradation states of quality-related components of the machine. Based on the response model, a process model is developed to quantitatively describe the impact of process variables on product quality. An integrated reliability model is built for the machine based on the proportional hazard model considering the effects of the degradation states of quality-related components on machine reliability. Quality loss is incorporated into the total cost, which is minimized to obtain the optimal PM schedule. A case study is conducted to illustrate the effectiveness of the joint model. It shows that the joint model can achieve a superior economic performance to the conventional PM model in general case. Economic benefits can be created by integrating quality improvement into PM decision-making. (C) 2015 Elsevier Ltd. All rights reserved.