The European funded project “Anisotropic fast prototyping of magnetic materials (aProMag)” aimed to prototype and validate additive manufacturing for fast prototyping of rotors for brushless DC motors and actuators. The cutting-edge technology will reduce waste by using state-of-the-art printing technology, enabling a reusability of up to 5 times with a material yield of approx. 97 %. The feedstock supply could be displayed by using recycled materials obtained from EOL NdFeB magnets and/or from primary sources, which will be suitable for a circular economy. This technology can shorten the manufacturing time of prototypes or final products to significantly reduce the costs compared to conventional injection molding manufacturing.

To produce anisotropic polymer bonded magnets via additive manufacturing, Pforzheim University investigated an entirely new method within the project. The investigated Cold Metal Fusion (CMF) process provides different benefits, like lower processing temperatures and control, but was just optimized for the use of stainless steel and titanium material grades by now. Due to the lack of suitable feedstock material for polymer bonded magnets, we developed material combinations for the first time within the project. For the manufacturing, the adaptable and programmable L-PBF system AMP Platform S3 has been used. The feedstock material was synthesized with a wax-based polymer system including 10 vol. % of SmFeN magnet powder (provided by Nichia Co., Japan) as a starting material. Process parameters for the powder filling, handling and fusing were manually set and had suitable values at a laser power of 30 W, laser scanning speed of 9 m/s, laser path spacing of 75 µm and a powder temperature of 45 °C. The as-produced samples have an undefined surface and couldn’t reach final part geometry, due to the still too high energy input by the laser, but still showed a dense microstructure with globally homogeneous magnet powder distribution (locally agglomerated). The magnetic properties reached a coercivity HcJ of 503.1 kA/m and a remanence Br of 84.6 mT. These results fit well in the linear rule of mixture of the SmFeN material, which leads to the conclusion that a proof of concept for the production of anisotropic polymer-bonded permanent magnets by CMF is given.