Analysis of a production line subject to degradation and preventive maintenance

Abstract

This paper considers a continuous flow manufacturing system with two machines subjected to condition-based preventive maintenance, and separated by an intermediate buffer of finite capacity. Each machine can degrade into several discrete states characterized by different degradation levels and performance parameters, ranging from perfect functioning to complete failure. Unlike the existing literature, the proposed approach considers various side effect costs, including the cost related to quality deterioration. A methodology is developed to describe the degradation stochastic process, and to analyze the complex trade-off between the condition-based preventive maintenance and the buffer capacity. The obtained results show the importance of considering quality-related and other possible costs when selecting preventive maintenance policy to optimize the performance of the manufacturing system. It is also shown that the selection of preventive maintenance actions should be considered from the view of the whole system, rather than individual machines. The optimal solution depends on the different degradation levels of the upstream and downstream machines.