Modeling the Impact of Laser Powder Bed Fusion on Nd-Fe-B Permanent Magnets

Statistical modelling was successfully applied to Laser Powder Bed Fusion (LPBF) of Nd-Fe-B permanent magnets to identify the potential impact of different process parameters and their interactions on resulting magnetic properties. Process models for the magnetic properties coercivity Hc, remanence Jr as well as for the shape of the demagnetization curve are obtained. The model quality for Hc is excellent (R2 = 0.99). The model for Jr only allows a rough statement on the impact of the LPBF process due to a weaker quality of the model (R2 = 0.77). It will not be possible to maximize Hc and Jr of LPBF manufactured Nd-Fe-B magnets at the same time due to their contrary dependencies on different LPBF parameters. We have predicted an optimized parameter set with a resulting high Hc of 816 kA/m and a maximized Jr of 0.65 T. From these properties and the calculated shape of the demagnetization curve we predict a (BH)max of 60.77 kJ/m3 for a magnet processed on a LPBF machine AconityMINI using MQP™-S powder.