While making strong magnets is not a very demanding task in terms of technology, precisely controlling the orientation of magnetism has been difficult to achieve. That is, until now – engineers at TU Wien had recently succeeded in designing and producing magnets using a low-cost, end-user 3D printer.
“The strength of a magnetic field is not the only factor,” said Dieter Süss, a materials scientist at TU Wien. “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.”
With the advent of 3D printers, researchers can finally apply the know-how required for producing tailor-made magnets, replacing the traditional injection-mould technology, which proved too clunky and expensive for producing small quantities of desired product.
The new technique is presented in the latest issue of the academic journal Applied Physics Letters.
First, the “printer” uses a digital 3D model to create an intricate geometric pattern from specially produced filaments of micro-granulate, held together by a polymer binding material. The printer heats up the micro-granulate and applies it point by point in the desired locations using a nozzle, resulting in a 3D object composed of roughly 90% magnetic material and 10% plastic.
Since the granulate is deployed in an unmagnetised state, the end-product is exposed to a strong external magnetic field that endows it with the intended permanent magnetic properties.
“This method allows us to process various magnetic materials, such as the exceptionally strong neodymium iron boron magnets,” explained Süss. “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.”
The new technique is quick, cost-effective and useful not only in sensor and electric drive technologies, but also for new applications altogether. According to the study authors, the next step will be to test the limits and see how far the technology can go.