# Predictive Maintenance for Remanufacturing Based on Hybrid-Driven Remaining Useful Life Prediction
###### Abstract  
Remanufacturing is an activity of the circular economy model whose purpose is to keep the high value of products and materials. As opposed to the currently employed linear economic model, remanufacturing targets the extension of products and reduces the unnecessary and wasteful use of resources. Remanufacturing, along with health status monitoring, constitutes a key element for lifetime extension and reuse of large industrial equipment. The major challenge is to determine if a machine is worth remanufacturing and when is the optimal time to perform remanufacturing. The present work proposes a new predictive maintenance framework for the remanufacturing process based on a combination of remaining useful life prediction and condition monitoring methods. A hybrid-driven approach was used to combine the advantages of the knowledge model and historical data. The proposed method has been verified on the realistic run-to-failure rolling bearing degradation dataset. The experimental results combined with visualization analysis have proven the effectiveness of the proposed method. c 2022 20 March 2022220 March 2022220 March 202220 March 2  
a combination of reused and repaired components to rebuild the as-good-as-new conditioned manufactured product. The main process includes disassembly, cleaning, inspection, repairing and replacing parts and reassembly. It not only saves the cost of manufacturing, but also reduces the consumption of energy and materials. Remanufacturing could save up to 80% of the cost and 85% of the energy of using new components [11; 12]. Although remanufactured products have been used in several industrial sectors, when and how remanufacturing should be conducted is still a challenge facing manufacturers [13]. For remanufacturing, there is an ideal high remanufacturability zone that has the optimal remanufacturability and its cost [14]. The remanufacturability is a criterion for the component of future remanufacturing [15; 16]. It considers the following factors: the quality of the component before remanufacturing, the importance of the component, the technology used for remanufacturing, and the customer awareness of component remanufacturing. These factors were considered in the proposed method to thoroughly assess the remanufacturability of the component. For a new component, reliability is an important factor for assessing degradation and indicating quality. As the component deteriorates over time, the remaining useful life becomes shorter while the reliability of the component decreases. If the reliability is below the lower threshold of the 'high remanufacturability zone', the remanufacturability of the components will not be sufficient, and the cost of remanufacturing will become too high. As shown in Figure 1, preventive maintenance can help maintain the remaining useful life (RUL) of components within the high remanufacturability zone. In the left figure, the yellow line indicates service time with maintenance. Maintenance actions are carried out according to the level of reliability during this period. Each time after the maintenance, reliability becomes higher than before, and the remanufacturability remains in a high zone. Accordingly, as shown in the right figure, the cost of remanufacturing, the remanufacturability and the value of the equipment are changing along the time dimension. In the 'high remanufacturability zone', the remanufacturability is kept high, while the cost of remanufacturing is relatively low, and the value of the equipment is still acceptable. Therefore, it is worth noting that predictive maintenance could support remanufacturing very effectively, allowing experts to make the optimal decision in such a framework. Predictive maintenance (PdM) is designed for evaluating the state of the in-service machine and generating a plan for when maintenance should be performed [17]. It is considered condition-based maintenance which is based on the estimated performance of degradation of the equipment.