Adzhamskyi S. Synthesis of design and technological solutions for manufacturing parts of rocket and space technology using selective laser melting

Adzhamsyi S.V. Synthesis of design and technological solutions for the manufacture of rocket and space technology parts using selective laser melting. — Qualification scientific work regarded as an equivalent to a manuscript. The dissertation for seeking the scientific degree of Doctor of Philosophy (PhD) in specialty 134 – “Aviation and Rocket and Space Technology”. – Oles Honchar Dnipro National University. – Dnipro, 2021. The dissertation work is devoted to the development of technological parameters and methodology for their obtaining for the modern process of 3D- printing of complex parts with the provision of certain quality indicators for manufacturing in aviation and rocket and space technology using the technology of selective laser melting (SLM). Modern rocket and space technology has passed a significant way of technological evolution and it uses the most advanced methods of design, engineering and production. The use of a large number of complex processes and principles enables production of parts of components and aggregates that are able to work on the limits of physical capabilities of structures and materials used. One of the key problems of the production of rockets and space vehicles (RSV) is the need to use a wide range of complex technological processes and unique production and testing equipment. In addition, the industry needs appropriate highly qualified personnel. The maintenance and development of this direction causes high costs, and, as a result, a sufficiently high cost of space missions. Recently, several areas of development of the latest technologies have emerged, which can significantly reduce the costs and production time in rocket and space technology and make production of the most complex systems of the launch vehicle easier: the pneumatic and hydraulic system, combustion chambers, turbo pumps and others. One of the key directions is the use of additive technologies, namely, 3D printing of metal parts. The key technology of 3D printing of high-quality complex products made of heat-resistantand nonferrous alloys is the process of "selective laser melting" (Powder Bed Fusion). This technology involves local layer-by-layer melting of metal powder in an airtight chamber filled with inert gas, with residual oxygen of less than 0.1 percent. As the source of energy, ytterbium fiber lasers with high radiation stability are used. The power of their radiation of 100 to 1000 W is optically focused into a spot of 50 to 300 μm. Geometric zones of melting and fusion are formed according to a preliminarily prepared program obtained by mathematical and algorithmic slicing a 3D model into layers and forming the trajectories of the laser beam.