Impact of Preventive Maintenance on the Service Level of Multi-stage Manufacturing Systems with Degrading Machines

In manufacturing systems, preventive maintenance plays a fundamental role in keeping and improving the operational condition of machines and the output product quality. However, preventive maintenance policies affect the available productive time of the system. This directly influences the lot completion time and delivery dates of customer orders. Therefore the choice of preventive maintenance policies needs to be taken by jointly considering the actual condition of machines and the impact of these policies on the service level of the system. This paper proposes an analytical approach for the analysis of the impact of preventive maintenance on the service level of manufacturing systems characterized by degrading machines. The actual degradation state of critical machines is inferred from condition monitoring information gathered by sensor networks. The results obtained from the application of the method to a real industrial case in the aeronautics industry show that the decisions on the optimal maintenance policies depend on both the actual status of machines and the target lot completion time, thus paving the way to new service level oriented maintenance policies.