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Combined production-maintenance decisions in situations with process deterioration

This article addresses an imperfect production system with process deterioration and how best to maintain the system. In the system there is a constant percentage to produce defective products in the ‘in-control’ state and a higher percentage to produce defective products in the ‘out-of-control’ state. The production process may shift randomly from an in-control state to an out-of-control state during a production run; i.e. system process deterioration. This article considers both preventive maintenance and corrective maintenance. The objective is to determine the optimal production run time and preventive maintenance frequency while still minimising the total annual cost. We provide two efficient algorithms for solving the problems when considering the preventive maintenance frequency as discrete and continuous, respectively. Finally, we apply a numerical analysis to study the effects of changing parameter values on the optimal solutions and to point out some management implications.