3D printer of domestic production
Russian scientists have created the first "real" 3D printer
Russian biologists and physicists have created unique nanoparticles that allow printing three-dimensional structures of any shape and any size in one sitting using a conventional infrared laser. Instructions for assembling a 3D printer based on them are published in the journal Scientific Reports (Rocheva et al., High-resolution 3D photopolymerization assisted by upconversion nanoparticles for rapid prototyping applications).
"This idea can be applied for biomedical purposes, in particular, in tissue engineering, replacing damaged parts of organs and tissues with various polymer materials. We expect that our technology will allow us to create structures of the right size and properties inside living tissues to replace damage," said Kirill Khaydukov from the Federal Research Institute "Crystallography and Photonics" of the Russian Academy of Sciences, whose words are quoted by the press service of the Russian Academy of Sciences.
In recent years, scientists and engineers have created dozens of new types of 3D printers capable of printing with almost any materials, ranging from classical plastics to living cells and metal melts. These technologies have become very popular due to their versatility, cheapness and flexibility, but they are still not without drawbacks that prevent their spread so far.
For example, most of these 3D printers suffer from two interrelated problems - low resolution and slow operation. Both are due to the fact that such installations print three-dimensional structures in layers, applying new layers of plastic to the workpiece. In most cases, it is much easier and faster to carve the desired part from a single piece of plastic or metal than to wait for the printer to print it.
Khaydukov and his colleagues solved this problem and developed the first truly full-fledged three-dimensional printer. To do this, they created special nanoparticles capable of converting pulses of infrared radiation into ultraviolet beams.
How are nanoparticles, 3D printing and ultraviolet interconnected? The fact is that many polymers that are used both in similar printers and in industry are obtained by firing ultraviolet beams at a mixture of monomers and special substances that enhance the effect of light. UV rays split part of the polymer blanks and force them to combine into chains.
The problem lies in the fact that ultraviolet penetrates into such a mixture shallowly, and this does not allow the use of a photopolymerization reaction for the production of large-volume structures. For this reason, for example, dentists are forced to apply fillings in layers, treating each portion of the polymer material separately with light.
Russian scientists have managed to solve this problem with the help of nanoparticles made of sodium, thulium, ytterbium and fluorine, which allow to evenly distribute ultraviolet light throughout the thickness of the created three-dimensional structure. Infrared radiation is used as an energy source.
Polymer microbeads formed around individual frequency-boosting nanoparticles (upconversion nanoparticles, UCNP).
Larger microstructures obtained by the same method.
Networked granular and individual stellate microparticles. Drawings from an article in Scientific Reports – VM.
As physicists explain, a mixture of liquid blanks of polymer materials will be almost completely transparent to IR rays, unlike visible light or ultraviolet, so they will "shine through" their entire thickness and interact approximately equally with nanoparticles in the inner and outer layers of the future 3D structure.
According to Khaydukov and his colleagues, their brainchild is compatible with existing polymer materials, which makes it possible to use such 3D printers in practice right now. As they hope, this idea will find application in three-dimensional laser drawing, micro-processing of materials, in holography, as well as in electronics and data processing systems.
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