Additive manufacturing of toroid inductor for power electronics applications

A commercial multi-extruder paste-extrusion 3D printer was used to process both metal and magnetic pastes into 3D structures of magnetic components for power electronics circuits. For the magnetic core, we formulated a permalloy powder filled benzocyclobutene composite in the form of paste, termed poly-mag paste, as a feed stock for the printer; while for the conductive winding feed stock, we used a commercial nanosilver paste. A toroid inductor was 3D-printed by using the metal and magnetic pastes, and it was cured at 250
^o
C for a half hour without any external pressure to form the structure. The inductance of the 3D-printed toroid inductor was measured to be about 110.3nH. The DC resistance of the winding was 0.28Ω. Both the winding and core magnetic properties can be improved by adjusting the feed paste formulations and their flow characteristics and fine-tuning the printer parameters, such as motor speeds, extrusion rate, and nozzle sizes.