Maintenance gravity window based opportunistic maintenance scheduling for multi-unit serial systems with stochastic production waits

This paper proposes an Opportunistic Maintenance (OM) scheduling model for the multi-unit serial system subject to random production waits. With the stochastic nature of production waits involved, the pre-scheduled Preventive Maintenance (PM) time for each unit changes from a specific time to a time window. To effectively group the PM activities of the units with a series of time windows, a new concept called Maintenance Gravity Window (MGW) is introduced and then a novel MGW based OM policy is developed. Whenever one of the units reaches its PM threshold or accepts a production wait to conduct PM, a PM opportunity for the system arises. At that time, all the other units, which also reach their own PM thresholds or accept this production wait, or whose gravity related to the current PM opportunity is within the MGW, will be preventively maintained together with this unit. The optimal MGW for the system is obtained by minimizing the total maintenance cost per unit time throughout the PM scheduling horizon. Finally, numerical examples and comparisons are illustrated to show the cost-effectiveness of the proposed MGW based OM policy.

Automated summary

This paper introduces an Opportunistic Maintenance (OM) policy based on Maintenance Gravity Window (MGW) for a multi-unit serial system, aiming to minimize the total maintenance cost per unit time. By introducing the concept of MGW, the optimal maintenance cost per unit time is achieved throughout the Preventive Maintenance (PM) scheduling horizon.