Using sintered neodymium–iron–boron (NdFeB) cube magnets and additively manufactured polylactic acid (PLA) and steel frames, we investigate hybrid manufacturing approaches for enhancing magnetic fields in cylindrical Halbach arrays while reducing reliance on critical rare-earth materials. Nested Halbach geometries with eight discrete dipolar segments were selected to balance magnetic performance with construction simplicity. The inner Halbach ring consisted of eight N48 NdFeB cube magnets, while the outer ring employed either additional NdFeB cubes or hybrid configurations incorporating additively manufactured steel elements. Experimentally, introducing a second Halbach ring of eight NdFeB cubes increased the lateral magnetic field by only ∼5%, indicating strong geometric and finite-length limitations in discretized arrays. In contrast, the axial magnetic field increased by ∼27% when 16 soft-magnetic steel cubes were incorporated into the outer ring. Notably, the lateral field enhancement achieved using eight NdFeB cubes combined with 16 steel cubes was comparable to that obtained using a full outer ring of 24 NdFeB magnets, despite substantially reduced permanent-magnet content. Ansys Maxwell Multiphysics simulations show that finite array thickness, magnet segmentation, alignment tolerances, and contour-driven demagnetization effects associated with discrete magnet geometry and array boundaries strongly suppress idealized field enhancements. These results demonstrate the potential of hybrid manufacturing to achieve competitive magnetic performance using lightweight, application-specific nested Halbach array architectures while reducing the criticality of high-grade permanent magnet materials.
Cosgrove et al. (Sun,) studied this question.