Preventive Maintenance and Replacement Policies for Deteriorating Manufacturing Systems

This paper presents the integration of preventive maintenance into the repair/replacement policy of a failure-prone manufacturing system. The system exhibits increasing failure intensity and increasing repair times. To reduce the subsequent repair time following a failure, a preventive maintenance is performed on the machine before failure. The decision variables of the system are the repair/replacement switching age at the time of the machine's failure and the preventive maintenance rate. The problem is formulated as a semi-Markov decision process. Numerical methods are given in order to compute optimal policies which minimize the average cost incurred by preventive maintenance, repair and replacement activities over an infinite planning horizon. A numerical example is given and sensitivity analysis are performed to illustrate the usefulness of the proposed approach and to confirm the structure of the obtained control policies.