Additively Manufactured Fe-3si Stator for a High-Performance Electrical Motor

Abstract

Additive manufacturing has the potential to produce novel high-performance electrical machines enabling direct printing of complex shapes and simultaneous processing of multiple feedstocks in a single build. We report properties and functional performance of Fe-3wt.%Si material that is printed by selective laser melting, machined down to thin laminates, and stacked to form a stator core of a prototype brushless permanent-magnet electrical motor. Big Area Additive Manufacturing (BAAM) of Nd2Fe14B (NdFeB)-polyphenylene (PPS) sulfide bonded magnets are magnetized and used for the rotor. The magnetic, mechanical, and electrical properties of the as-printed and various heat-treated thin laminates and the back electromotive force (emf) of the electrical motors at different rotational speeds are measured. The thin laminates exhibit a maximum relative permeability of 7,494 at an applied field of 0.8 Oe, and a core loss of about 44 W/kg at 60 Hz with the maximum induction of 15 kG. In addition to demonstration of AM printing, motor assembly and complete characterization of printed Fe-3wt.%Si, this report highlights the areas of improvement needed in printing technologies to achieve wholly AM built electrical motors and need of isotropic microstructures refinements to make the laminates appropriates for high mechanical strength and low loss rotational electrical devices.

Keywords: soft magnetic materials, Fe-3wt.% Si, selective laser melting, BAAM isotropic NdFeB PPS magnets, electrical motors