When I went to New York some years ago, I received four pieces of advice from a Texan gentleman philosophizing in an Irish Bar. The first three nuggets of wisdom he gave me were the vague kind of advice you’d expect e.g. ‘always have an out’, but the last one, in contrast, had a laser-like precision: Magnets, he said if you figure those out they’ll have a statue of you in Times Square. Fast forward to the present day, and researchers at TU Wien in Vienna have mastered how to control magnetic fields by using 3D modelling design methods and a 3D printer. No fuss. No fanfare. No statue of them in Times Square (yet).
“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 the 3D print of polymer bonded rare-earth magnets, and 3D magnetic field scanning with an end-user 3D printer project.
Magnets, how do they work?
Much like the mysterious Texan I met in New York, the production of magnets is hard to comprehend. Even these 3D-printed magnets have to be exposed to an external magnetic field before they become permanently magnetized. But it is done this way to ascertain the desired shape of a magnetic field. As we previously reported on 3DPI in March, a California enterprise by the name of Correlated Magnetics is also active in this area.
These magnets are 3D printed using a composite filament of magnetic micro granulate (MMG) and a plastic polymer binding, at an approximate ratio of 90 parts commercially available NdFeB magnetic granulate to 10 parts Nylon/Polyamide 11 bioplastic. The team used a commercially available 3D printer for the project, and created models using CAD software. Dieter Süss, Head of the Christian-Doppler Advanced Magnetic Sensing and Materials laboratory at TU Wien commented,
Magnet designs created using a computer can now be quickly and precisely implemented – at a size ranging from just a few centimeters through to decimeters, with an accuracy of well under a single millimeter.
Fabrication in this way brings to magnets all of the main attributes we’ve come to expect of additive manufacturing. It means that magnet production is both time and cost effective, while being precise and entirely custom-designed.
!["[The above] shows a picture of the printed magnet with the isotropic Neofer® 25/60p material. The overall size of the magnet is 7 × 5 × 5.5 mm (L × W × H) with a layer height of 0.1 mm, and features with a thickness of 0.8 mm. This indicates the possibility to print miniaturized magnets with complex structures." Image via: Appl. Phys. Lett. 109, 162401 (2016)](https://3dprintingindustry.com/wp-content/uploads/2016/10/3D-printed-magnet-e1477413147875.jpg)
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.
This development also means that new materials could be spliced into the structure of magnet, allowing researchers to further manipulate its magnetic properties. Dieter Süss closed his statement on the paper by saying 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, which certainly serves to put a finer point on my assertion that a manipulation of magnets is something deserving of a statue. Perhaps one appropriately 3D printed using FDM.
Featured image is of Magneto taking apart an android using his magnetic power. Image from: Marvel comics.
