3-D Printing of Multipolar Bonded SmCo Permanent Magnets

The use of permanent magnets (PMs) in electrical machines and actuators makes it possible to achieve high performance in terms of torque or force density and efficiency. PMs can be manufactured either by sintering or bonding methods. Bonded magnets are weaker than sintered ones, but are easier to manufacture. In exploring the use of 3-D printing to speed up and reduce the cost of permanent bonded magnet manufacturing, this article describes the production of filament material based on a mixture of SmCo powder and PA12 polymer and then explains how a customized commercial 3-D printer is adapted to print permanent bonded magnets with specific magnetization patterns on the plane of the heating plate. This adaptation applies an in situ magnetic field during printing to orient magnetic particles toward the flow direction. This magnetic field is created with specifically designed PMs. With this machine, it is possible to print unipolar and multipolar bonded SmCo PMs with special magnetization patterns (alternating poles, Halbach).