Magnetic Patterning of Permanent-Magnet Rotors for Microscale Motor/Generators

Abstract : We present and characterize a process to pattern magnetic poles on small permanent-magnet (PM) rotors used in microscale, axial-flux, PM machines. Unlike other previously reported approaches, this approach uses a ferromagnetic magnetizing head (MH) and an externally applied magnetic field, and it offers the potential for moderate scalability and batch-magnetization of multiple parts. The process is verified using 8-pole annular PM rotors with thicknesses of 500 micrometers and 9.5 mm outer diameters. 3-D magnetostatic, finite element analysis (FEA) is employed to examine the process and to verify the experimental magnetization patterns.