Review of additive manufacturing of permanent magnets for electrical machines: A prospective on wind turbine

Permanent magnets (PMs) power several industrial technologies that enable our modern society and high standards of living. As such technology becomes more advanced and widespread, the demand for PM-based motors and generator increases, and thus the demand for PMs themselves increases. Additive manufacturing (AM) could be an attractive method for manufacturing PMs, as it minimizes the use and waste of critical, supply-limited rare earth materials and enables near-net-shape printing of complex geometries. In this work, the critical roles that PMs play, as well as the challenges and difficulties in utilizing them, are discussed. The conventional manufacturing processes for PMs are explored, and their advantages and disadvantages are highlighted. The advantages of AM are briefly introduced. Then, a survey of the major PM materials is provided, which introduces the major magnet families and summarizes their material properties. The benefits and advantages of AM over conventional methods in creating PMs are explored in detail. After that, the AM processes that have been used to manufacture PMs are reviewed, and the AM research efforts relating to each type of these PMs are explored. The magnetic and thermal properties of AM of PMs are reported in detail. For example, printed Nd2Fe14B magnets with suitable polymers can be operated at as high as 175 °C with improved corrosion resistance. There is a focus in this paper on the use of AM PMs on wind turbine generators and large electrical machines across all sections. The future outlook of the use of AM processes for PM manufacturing is also provided. •Perspective of additive manufacturing (AM) of hard magnetic materials.•AM processing of magnetic materials and their integration in electrical machines.•Magnetic, electrical, mechanical and thermal properties of printed parts.•AM magnets outperformed traditional injection molded magnets.•Promise for fabricating all 3D printed motors and generators with improved efficiencies.