Joint optimization of lot sizing and condition-based maintenance for multi-component production systems

- A joint model of EPQ and CBM for multi-component systems is proposed.
- Both the structural and economic dependencies among components are considered.
- The PM policy is based on the predictive reliability and structural importance.
- A cost model is developed and the optimal joint policy is obtained numerically.
- The use and advantages of the model are illustrated through a case study.

This paper presents a joint optimization model of production lot sizing and condition-based maintenance for a multi-component production system which produces the products to meet the demand in a finite time horizon. The components in the system deteriorate gradually with usage and age. To evaluate the conditions of components, inspections are carried out after each production run. The condition-based maintenance decision-making rules are based not only on the predictive reliability but also on the structural importance of each component. Moreover, the economic dependency among components is also considered when performing corrective maintenance actions. The preventive maintenance cost, the corrective maintenance cost, the setup cost, the inspection cost, the inventory holding cost and the shortage cost are considered in this paper. The aim is to minimize the total cost by jointly optimizing two decision variables: the production lot size and the preventive maintenance threshold. The optimal joint policy is obtained by coupling simulation model and genetic algorithm. Finally, the use and advantages of our model are illustrated through a case study of a cluster tool.