Yangtze River Delta G60 Laser Alliance Introduction
It is reported that scientists from Ural Federal University and Ural Branch of the Russian Academy of Sciences are determining the best conditions for 3D printing of permanent magnets based on rare earth metal . This will enable small-scale production of magnets, giving them any shape during the manufacturing process and creating complex magnet configurations. This magnet is suitable for pacemaker micro motors and generators. In addition, this technology minimizes production waste and shortens the production cycle . The description of the method and experimental results were published in the journal Magnetism and Magnetic Materials. Miniature permanent magnets printed on
3D printer. Source: UrFU / Oksana Meleshchuk
Making complex and small magnets is not an easy task, but they are in demand in a variety of specialized applications, mainly in the medical field. One of the most promising ways to make complex-shaped parts with magnetic hard materials is 3D printing. Scientists successfully determined the best parameters for 3D printing of permanent magnets using the selective laser sintering method.
This is an additive manufacturing method that sinters a magnetic material in powder form layer by layer into a three-dimensional product of a given shape based on a previously created three-dimensional model. This technology makes it possible to change the internal characteristics of the magnet at almost all stages of production. For example, the chemical composition of the compound, the spatial orientation degree and crystal texture of the crystal , and the coercive force (anti-demagnetization). Sample image and printing strategy after
SLM. The red line represents the laser beam spot trajectory; the black dotted line shows the movement of the beam focus and the laser is closed.
"Producing small magnets is a difficult task. Now they can only be made by cutting a large magnet into small pieces, and due to the machining, about half of the used material becomes garbage. At the same time, cutting introduces a large number of defects in the near-surface layer, which greatly deteriorates the performance of the magnet. Adding technology can avoid this and create complex magnets. Such a configuration is necessary for pacemakers, because only under a microscope can the rotor of the motor be assembled from a standalone magnet," explained researcher Dmitry Neznakhin.
In order to print the magnet, scientists poured special steel powder into the printer. Source: UrFU / Oksana Meleshchuk
Currently, scientists have successfully made permanent magnets about one millimeter thin, with similar performance to those produced by industrially. The base is a powder containing samarium, zirconium, iron and titanium. The compound has properties suitable for permanent magnets, but traditional manufacturing methods deprive most of the properties of the compound. Therefore, scientists decided to see if new technologies can preserve these characteristics.
"When using traditional methods to prepare permanent magnets based on these compounds, the performance of the finished product is far from what is predicted by the theoretical prediction. We found that when sintering the sample, the addition of fusible powder extracted from samarium, copper and cobalt alloys can retain the magnetic characteristics of the main magnetic powder. The melting temperature of this alloy is lower than the performance variation of the main alloy, which is why the final material maintains its coercive force and density," added Dmitry Neznakhin.
Figure 4 SEM image of SLM (Sm1−xZrx)Fe11Ti magnet at x = 0.2: (1) Epoxy resin; (2) Low melting point additive; (3) (Sm1-xZrx)Fe11Ti fast quench alloy, (4) Interaction zone.
At present, scientists are establishing the basic formation rules of the microstructure and magnetic properties of hard magnetic materials, and determining which magnetic materials can be used to make permanent magnets by laser sintering. This includes testing how the sintering method affects the properties of another known magnetic matrix—an alloy of neodymium, iron and boron. The next phase of work will be to produce large permanent magnets suitable for practical applications.
Source: Phase composition and magnetic properties of (Sm,Zr)Fe11Ti magnets produced by selective laser melting, Journal of Magnetism and Magnetic Materials (2022). DOI: 10.1016/j.jmmm.2022.169937
Yangtze River Delta G60 Laser Alliance Chen Changjun reprinted
