Integrated control policy of production and preventive maintenance for a deteriorating manufacturing system

This paper addresses the integrated control of production and preventive maintenance for a deteriorating single machine manufacturing system. The machine is subjected to deterioration and random failures. Both corrective maintenance and preventive maintenance are performed to maintain the machine's reliability. The previous literature in this field normally assumes the periodicity of preventive maintenance and obtains only its fixed time interval for execution. Maintenance level, which represents the time and cost invested in the maintenance activity, is usually ignored in the literature. Therefore, we propose an integrated control model that considers not only the flexible time interval of preventive maintenance but also its level. The problem is then formulated as an infinite time horizon dynamic programming problem of a semi-Markov decision process. The objective is to develop the optimal control policy in terms of production rate, hedging level, maintenance rate and maintenance level such that the total production cost is minimized. The successive value iteration algorithm is applied to obtain the near optimal control policy. We compared the obtained policy with previous control policies reported in the literature through several numerical examples. Additionally, sensitivity analysis is performed to illustrate the impact of several cost parameters on the control policy and to validate the structure of this policy. This paper contributes to fill the research gaps mentioned above and provides a more practical production and preventive maintenance control model for industrial practitioners.