Novel Method for Overmolding of NdFeB Bonded Magnets Into a 3-D Printed Rotor

The need for high-performance magnets has dramatically increased in recent years to meet the demands of modern electronics used for both commercial clean energy and consumer products. Wind energy has especially increased demands for high-performance magnets because of the unique large power density and high conversion efficiency the powertrains require. Exciting new materials that meet these requirements include Nd/DyFeB, SmCo, and SmFeN-based permanent magnets. To reduce the waste of materials used in production, manufacturing techniques like compression molding are necessary. The work presented here compression molds a blend of Nd2Fe14B (NdFeB) and Sm2Fe17N3 (SmFeN) hybrid powders in a polyphenylene sulfide (PPS) polymer matrix over a 3-D printed iron silicon rotor. Vickers and nano-hardness is measured of both the polymer blend and as well as the steel rotor. Small piece of the inserted magnet has a measured energy product of 8.324 MGOe through a post magnetic field annealing. Post-magnetic field annealing of the whole overmolded sample is necessary in the future. The demonstrated method provides a pathway for making high performance printed electric motors and generators.