Joint optimization of preventive maintenance and economic production quantity with considering demand adjustment

An integrated cost model for jointing preventive maintenance (PM) and economic production quantity (EPQ) in a multi-product system is proposed in this paper. Assume the production horizon is finite, which is composed of several production cycles, some types of the products should be produced in lots within the cycles. For less disturbing to the production process, and according to the situation in reality, we also assume PM should be done at some setup time epoch. The demand should be adjusted because the downtime caused by maintenance and setup is random. The objective of this paper is to optimize EPQ and PM schedule through minimizing the expected cost per product influenced by adjustment coefficient of demand within the planning horizon. A case study is presented to show the availability of the model.