New Scanning Strategy Approach for Laser Powder Bed Fusion of Nd-Fe-B Hard Magnetic Material

Abstract

Volumetric cubic and cylindrical samples from MQP-S Nd-Fe-B-type material were 3D-printed using the LPBF technique. Two different scanning strategies were used: the convenient single laser exposure scanning strategy and the newly proposed double scanning strategy aimed at improving the melting process and increasing the density of the synthesized material. Samples with a relative density value higher than 95% were obtained using the new scanning strategy by reducing void volume and cracks. This was achieved by decreasing internal stresses and reducing the tendency to form and propagate cracks. The double scanning strategy of half laser power followed by full power exposure provides higher magnetic properties (both coercive force and remanence). The coercive force increases with energy input decrease, while remanence has inverse dependence.

Keywords

• laser powder bed fusion
• selective laser melting
• hard magnetic material
• permanent magnet
• rare earth intermetallic
• 3D printing