Different magnetic materials can be used. Credit: TU Wien
How can a magnet be produced with precisely the right magnetic field? A team of researchers from TU Wien has a solution for the first time: a 3D printer can make magnets.
From a technical perspective, developing strong magnets is not a problem today. However, it is difficult to make a permanent magnet with a specific magnetic field of a pre-determined shape.
Now, for the first time ever, the new solution created at TU Wien can produce permanent magnets using a 3D printer. This solution allows magnets to be created in a complex forms and, in particular, customized magnetic fields, required, for instance, in magnetic sensors.
Designed on a Computer
The strength of a magnetic field is not the only factor. We often require special magnetic fields, with field lines arranged in a very specific way – such as a magnetic field that is relatively constant in one direction, but which varies in strength in another direction.
Dieter Süss, Head of the Christian-Doppler Advanced Magnetic Sensing and Materials laboratory at TU Wien
Magnets have to be created with a sophisticated geometric form in order to get such requirements.
“A magnet can be designed on a computer, adjusting its shape until all requirements for its magnetic field are met,” explains Christian Huber, a doctoral student in Dieter Süss’ team.
How can the design be implemented once the desired geometric shape is achieved? One solution is the injection molding process, however this requires the formation of a mold, which is expensive and time-consuming, making this process barely worthwhile to produce small quantities.
Tiny Magnetic Particles in the Polymer Matrix
Now, a much simpler process is available. Researchers at TU Wien created the first-ever 3D printer that can be used to produce magnetic materials. 3D printers that produce plastic structures have existed for a while, and the magnet printer functions in the same way.
However, the dissimilarity is that the magnet printer uses specially generated magnetic micro granulate filaments, where the granulate is held together by a polymer binding material. The printer heats and applies the material point by point in the preferred locations by means of a nozzle. The acquired result is a three-dimensional object made of roughly 10% plastic and 90% magnetic material.
The end product is not yet magnetic, because the granulate is applied in an unmagnetized state. At the end of the process, the resulting object is exposed to a strong external magnetic field, changing it into a permanent magnet.
This method allows us to process various magnetic materials, such as the exceptionally strong neodymium iron boron magnets. Magnet designs created using a computer can now be quickly and precisely implemented – at a size ranging from just a few centimetres through to decimetres, with an accuracy of well under a single millimetre.
Dieter Süss , Head of the Christian-Doppler Advanced Magnetic Sensing and Materials laboratory at TU Wien
A Whole World of New Possibilities
This new process is not only fast and cost-effective, but it also opens up new avenues that would be unthinkable with other methods, for example, different materials can be used within a single magnet to produce smooth transition between weak and strong magnetism.
“Now we will test the limits of how far we can go – but for now it is certain that 3D printing brings something to magnet design which we could previously only dream of,” declares Dieter Süss.