Russian aviation industry remains competitive. However, in order to conquer new markets tomorrow, it is necessary to create a competitive advantage today: to make products better and cheaper, to create flexible solutions and to expand its range.
These problems can be solved through the use of additive technologies, scientists of the All-Russian Scientific Research Institute of Aviation Materials (VIAM) are sure. Their project they implement within the FTP IR 2014-2020.
In VIAM additive manufacturing technologies are used for «growing» parts of a gas turbine engine (GTE). For this purpose, metal powders are laser co-melted. Powders themselves are prepared from nickel heat-resistant alloys.
"The main advantage of the use of additive echnologies is time-efficiency, - said Alexander Eugene. - A set of parts consumes many times less time than the conventional technology.
For example, to grow a set of swirlers 26-28 actually takes 20 to 22 hours. Cf. the two-month cycle in the factory! "
In addition to saving the time the technology of selective laser melting allows to save material 3 fold reducing the cost of manufacturing complex profile parts.
Of course, for mass production unit price is important. And, despite the fact that now the cost of the part, grown with the help of the developed technology is higher than the one cast at the factory, in the long term additive technology will get rid costs inevitable in casting.
"When at the factory some details are made in thousands of copies, of course, this will be cheaper. But if we say that the design of the part is to be changed (the most simple - to increase or decrease it), it is necessary to reset all the technology, said the head of the works. - This can take from six months to a year. With our technology you can make these changes in a matter of days, and also to make parts that cannot be obtained by casting, processing or compression. The future of this technology is not to replace the cast, but to make it easier to redesign the details. "
In the first phase of the project scientists, together with the"Aircraft Engine" industrial partner chose details that need to be manufactured by the developed technology.
Before growing parts a 3D-model is prepared. It is important to place it on the platform, taking into account the structure and size, and then construct the supporting elements that will keep the item itself and reduce residual stresses in metal during growth.
Upon completion of the work in 2017-2019 JSC «Aviadvigatel" plans industrial use of the developed additive technology that can be used in both military and civil aircraft construction.
For all the undoubted advantages of additive manufacturing, its use is now very limited in the Russian aviation industry. And it's not only the serious costs that will be required for reconstruction of existing production facilities, the problem is that they lack suitable "building materials".
Today, for the detail production imported metal powders are used but the sanctions showed that without domestic materials it will be hard to go on.
In addition, foreign powders supplied by manufacturers of systems for the cultivation of parts, have a very limited range of 8-10 alloy grades and for the production a wider range of possible raw materials is needed. Therefore, at least as important part of the project is the development of the technology of metal powders.
"The most difficult task of the project - is working out parameters of the process of selective laser melting. First, it is done on sample cubes 10x10 millimeters grown from powders of different dispersion. An experiment net is selected, different speeds of movement of the laser, different power, different size and strategy of strokes "- said Eugene.
At the moment, a technology to manufacture high quality metal powders has been developed based on heat-resistant nickel-based alloys where the method of gas atomization is used. This method consists of mechanical action of the inert gas (usually argon) at a high pressure over a jet of liquid metal. Preparation of powders by this method allows to form particles of a spherical shape, uniform in chemical composition and with the lowest content of harmful gas impurities. Engineers have already released the specifications for the powders (TU).
Well composed guide for the implementation of any technology is half the battle, said Alexander Eugene:
"Production is a frozen type of process. While there is working out on the way , the scientific and technical personnel and researchers are involved. And as soon as the technology is developed, an instruction is filed that defines all the parameters of the process: which metal-powder composition is used, which fusion process parameters are set for a specific powder, etc.
4 types of powders has already been obtained and approved during the project, working parameters for selective laser fusion of powders are already known, the support elements are designed for complex-GTE parts, regulatory documents are prepared and issued .