3D Printing of Magnetic Cores for Electrical Motors

This report briefly summarizes development of magnetic cores using binder jet printing technology via the investigation of the material magnetic properties. Eighty (80) samples were prepared with different material compositions and process parameter. Soft magnetic composite material was used as the base line comparison for this work primarily because SMC has been used for construction of unconventional motor topologies. The addition of boron as a sintering aid is shown to improve the performance of binder jet printed magnetic cores. Boron results in a eutectic reaction of Fe28 and Fe which shows as grain-boundary lamellae phase. The magnetic relative permeability of the optimized binder jet printed magnetic cores is nearly 6 times that of SMC. The optimized binder jet printed magnetic core also has lower hysteresis loss per cycle than commercially available SMC. The magnetic saturation flux density of the optimized binder jet printed magnetic core is 1.5T, similar to the maximum for commercially available SMC. A permanent magnet motor was designed and assembled using a binder jet printed magnetic core with cooling channels in each tooth. The motor was mounted and experimentally evaluated.