State-of-the-Art of 3D Printing in Remanufacturing Within Industry 4.0

This paper provides a state-of-the-art review of 3D Printing for Repair (3DP4R) systems within the framework of Industry 4.0 and the circular economy. Conventional remanufacturing face severe technical bottlenecks due to discontinued spare parts and high inventory costs, leading to prolonged equipment downtime. To address these limitations, this research analyzes the integration of Fused Deposition Modeling (FDM) as a decentralized, on-demand restoration strategy. A structured evaluation of the four-stage 3DP4R operational flow—Analysis, (Re)design, Additive Manufacturing, and Testing—is provided. The study evaluates critical engineering challenges, including the structural discrepancies between isotropic injection-molded components and anisotropic FDM layers, while emphasizing the optimization of internal infill parameters, raster orientation, and post-processing thermal annealing. Conclusively, this paper establishes a conceptual roadmap for digitized product life extension, demonstrating that leveraging digital twins transforms physical warehouses into sustainable digital inventories, thereby mitigating the environmental impacts of global industrial logistics.