Optimal Preventive Maintenance Policy for Deteriorating Production Systems

The traditional Economic Manufacturing Quantity (EMQ) model assumes that the production process (system) is perfect. However, owing to aging, the production process will shift from the ‘in-control’ state to the ‘out-of-control’ state and produce defective items. When the process shift distribution follows an Increasing Failure Rate (IFR) distribution, preventive (scheduled) maintenance policy is usually used to enhance its reliability. In this paper we incorporate a preventive maintenance policy into this deteriorating production system and derive an optimal preventive maintenance policy. Two well-known IFR distributions, Weibull and extreme-value distributions, are considered and some examples are used to illustrate the proposed model. Finally, the advantages of the proposed model are addressed in the conclusion.