Researchers in Austria have developed a technique to build magnets using additive manufacturing (writes Nick Flaherty).
Magnets for electric motors can now be built in complex shapes using additive manufacturing
The team, at Friedrich-Alexander- Universitat, worked with researchers at the Graz University of Technology, the University of Vienna and the research institute Joanneum Research to produce the specially designed magnets using a laser-based 3D printer.
Traditional manufacturing methods such as sintering or injection moulding cannot always cope with the increasingly challenging geometric requirements for magnets that can give a boost in performance.
For the 3D-printing technique, a powder of the NdFeB magnetic material is added layer by layer, and the particles are joined by melting them using the laser in a ‘melt track’. The process allows magnets to be printed with a relatively high density at the same time as controlling their microstructure. This allows researchers to tailor the magnetic properties to suit a particular application, such as an electric motor.
The researchers looked at the influence of changing laser power, scanning speed and powder layer thickness on density, porosity structure, microstructure, phase composition and magnetic properties. This work showed that the energy density coupled with powder layer thickness plays a crucial role in melt-track stability. It was possible to manufacture magnets with both high relative density and high magnetic properties.