Fully 3D-Printed Multilayer Axial Flux Stator for Rotary Electromagnetic Motors

Multimaterial additive manufacturing that combines electrically conductive materials with thermally conductive, but electrically insulating materials presents new opportunities for creating novel and complex electromagnetic actuators. While conductive inks have previously been used to print a wide range of circuits, sensors, and antennas, little effort has been made to additively manufacture high-current (
$>$
1 A), multilayer, and multicoil actuators, such as rotary electric motors. In this work, we design, manufacture, and characterize a novel, fully 3D-printed, multilayer three-phase electromagnetic stator for an axial flux rotary motor. The stator consists of 14 layers of six coils composed of silver nanoparticle ink deposited using direct-write printing onto electrically insulating and thermally conductive copper-filled polylactic acid filament deposited using fused deposition modeling. To demonstrate this concept, we first outline the material selection, stator design, and printing process. Then, models for the thermal characteristics and output motor torque are developed and compared with experimental results. Measurements indicate that the 3D-printed dual-rotor axial flux motor produces 1.5 N
$\cdot$
mm/A of torque without gearing, has a maximum 7.6% power conversion efficiency, and can operate continuously at up to 125 °C at 14.0 W (4.0 A) input power. To demonstrate the capabilities of a fully 3D-printed axial flux motor, a 3D-printed fan, gripper, and wheeled vehicle are demonstrated.