Additive Manufacturing of Nd-Fe-B Permanent Magnets and Their Application in Electrical Machines

Powder Bed Fusion-Laser Beam (PBF-LB), a form of additive manufacturing (AM) for Nd-Fe-B permanent magnets, is attracting substantial interest for its ability to process functional magnetic materials while capitalizing on AM's design flexibility and waste reduction. As the demand for rare-earth magnets declines due to scarcity and high costs, AM emerges as a pivotal player in the future of electrical machines. However, crack formation and delamination during laser-based AM hinder the production of hard magnetic Nd-Fe-B components, compromising part integrity. This paper addresses these challenges by successfully controlling laser scan strategies and presenting an approach to minimize delamination. Resin infiltration is explored as a potential solution to mitigate residual cracking. Optimized scan strategies and resin infiltration enhance the structural integrity of printed magnets, meeting specific application requirements. As a vessel to investigate the proposed approach for the AM of Nd-Fe-B magnets, a Permanent Magnet assisted Synchronous Reluctance motor has been designed using a particular shape of permanent magnets enabled by the AM. Experimental results align with the FE findings, showcasing a 12% increase in average torque using PBF-LB-produced permanent magnets. This indicates that AM's enhanced design freedom, unconventional shapes, and minimal post-processing contribute to improved reliability, efficiency, and overall performance.