Low-Field Alignment of Anisotropic Bonded Magnets for Additive Manufacturing of Permanent Magnet Motors

Additive manufacturing techniques for fabricating bonded magnets have the potential to reduce manufacturing cost and time-to-market of products and address the criticality of rare-earth elements (REEs), which is a concern for economic design of dependent applications such as permanent magnet machines. We investigated the magnetic alignment of anisotropic bonded magnet material comprising 65 vol.% Nd-Fe-B in nylon-12 produced by extrusion in a 20-W brushless direct current surface permanent magnet motor for submersible water pump application using finite element analysis. The results predict that sufficient alignment for this application could be obtained at low alignment fields (μ0H ≤ 1 T) with a reduction in the volume of critical materials by up to 40% compared with isotropic permanent magnets. This demonstrates the economic feasibility of incorporating a magnetic alignment field source into additive manufacturing systems for bonded magnets, and the potential of aligned anisotropic bonded magnets to address REE criticality