Efficient near Net-Shape Production of High Energy Rare Earth Magnets by Laser Beam Melting

Abstract

In this publication we report on our progress in investigating the energy efficient production of rare earth permanent magnets by Laser Beam Melting in the powder bed (LBM). This innovative additive manufacturing process offers the potential to produce magnets of complex geometries without an energy intensive oven sintering step. Another advantage that increases the efficiency of this possible new process route is the high degree of material utilization due to a near net shape production of the magnets. Hence only little material is wasted during a post processing machining step. The main challenge in processing rare earth magnet alloys by means of LBM is the brittle mechanical behavior of the material and the change in microstructure due to the complete remelting of the magnet powder. We therefor expanded the parameter study presented in previous work in order to further increase relative density and magnetic properties of the specimens. In this context process stability and reproducibility could also be increased. This was achieved by investigating the impact of different exposure patterns and varying laser spot sizes. Simultaneously to the experiments the energy consumption of the LBM process was measured and compared with conventional rare earth magnet production routes.