Today we continue our conversation with Vladimir Promakhov, Ph.D. in Engineering, Deputy Director at Additive Technologies Research and Educational Center. Last time, we discussed several projects that put TSU on the top of the Shanghai global ranking in metallurgical engineering.
- Information about your work with ceramics has appeared on the TSU website several times. One of the issues of our blog was devoted to the technologies for creating implants from titanium nickelide and it seemed to us that ceramics is such a... traditional material.
- Indeed, it has been studied rather sufficiently. But we started to use new technologies in working with him. In particular, a number of projects on additive technology for ceramics have been carried out. One of the results of our work with it was the creation of a 3D printer for ceramics, as well as the development of methods for obtaining suspensions from printing powders.
- How can you print something from ceramics? As far as we know, it doesn't melt, does it?
- This is true. You cannot fuse ceramics with a laser. However, it is possible to obtain ceramic products by using suspensions: a mixture of ceramic powder with paraffin and other additives. The powder floats in a pulp, this pulp is applied in layers, then all this is placed in an oven, the binder material burns out, and the ceramics are sintered at a high temperature. Unfortunately, this method of additive manufacturing of ceramic products gives poor surface quality: we see a nozzle with a diameter of 0.5 mm (it cannot be smaller, otherwise, it would clog) and a low print resolution is obtained. This can be compared to pixels in a photograph: the larger the pixels are, the grainier and poorer the image is. The surface of the product becomes ribbed, which is unacceptable for industrial production. It should be understood that after sintering, the ceramics cannot be processed with anything, because its hardness is higher than that of a diamond tool.
- How can this problem be solved?
- There is another method of producing ceramics using additive technologies when a ceramic powder is mixed not with a thermoplastic, but with a photopolymer binder, which hardens when exposed to laser radiation. In this case, the diameter of the laser beam is 30-50 microns (hundredths of a millimeter) and the surface is less grainy. This method improves the accuracy of printing, allowing having designs that are more complex. As we came to the end of our work on this method, our colleagues in the Netherlands, who had been working on the same issues, began to produce printers that could print this way. Despite the fact that they are still quite expensive (30-50 million rubles), there was no point in creating the same machine for us. But working on new formulations that can be used in such a machine was and still is really interesting and promising. This is what we are doing now in additive technologies.
A parallel project related to ceramics was its processing on a lathe controlled by a robot. We already know that after baking the ceramics cannot be treated with anything. For a very long time, we were 
looking for options for how products of complex shapes can be obtained from it on machine tools and have developed a technology for preliminary annealing when the ceramics is not too hard but does not crumble in our hands anymore. It can be fixed in the machine, processed with a special tool, sintered, and in the end, we have a ceramic element of excellent quality. This method cannot be applied in the production of very large or very small parts. This technology is well suited for the fabrication of medium-sized posts and implants. The production of such elements on a 3D printer is too expensive and unproductive, and on a lathe, they can be produced in the amount of 10,000 pieces per month. They are very cheap.
- Has the production been already launched?
- Not yet, but it will be launched rather soon, after having clinical trials, in one of the Tomsk companies that are part of the pool of small innovative enterprises around TSU. In the near future, ceramic blanks for the manufacture of dental prostheses will enter the market, which will have no analogs on the Russian market either in quality (it is provided by a Japanese powder material) or in price".
Editorial Board