Metal additive manufacturing for high-performance electrical machines: a review

Achieving high power density and ultra-high efficiency in electrical machines requires overcoming the inherent 2D geometric constraints of conventional mass-manufacturing methods. In this context, additive manufacturing (AM) enables the fabrication of complex, highly integrated components and emerges as a transformative approach for multidisciplinary optimization of mechanical and thermal performance. This critical review synthesizes the latest advances, key limitations, and future research directions for the application of AM to core electrical-machine components. The review covers the tailored optimization of soft magnetic materials, particularly Fe-Si and Fe-Co, processed via methods such as laser powder bed fusion (L-PBF) and binder jetting (BJT), and highlights the role of post-processing heat treatment (HT) in improving magnetic permeability and overall magnetic performance. It further examines AM-enabled winding concepts, including semi-stranded coil architectures and eddy-current-suppressing features, aimed at reducing AC losses under high-frequency operation. In addition, this study discusses state-of-the-art thermal management system (TMS) solutions, including hollow conductors with integrated heat pipes (HP) and phase change material (PCM)-based approaches for enhanced heat extraction and temperature regulation. Despite these developments, two critical challenges remain: uncertainty in thermal analysis driven by the surface roughness of AM-produced channels, and the unresolved goal of single-step, multi-material integration of magnetic, conductive, and dielectric materials. The review demonstrates that AM offers a key technological pathway for developing next-generation, high-performance electrical machines demanded by many industrial fields, including electrified aviation and advanced transportation systems.