Вступ. Технології адитивного виробництва останнім часом набувають все більшого поширення у сучасному виробництві, оскільки дозволяють швидко та якісно створювати вироби з унікальною геометрією.Проблематика. Для виробництва деталей необхідно використовувати раціональні технологічні параметри, які залежать від характеристик матеріалу та обладнання селективного лазерного плавлення (СЛП). Серед факторів, що впливають на механічні властивості, є такі як орієнтація в робочій камері побудови та товщина робочого шару.Мета. Дослідження впливу орієнтування зразків в напрямку осей X, Y, Z та товщини шару (40 та 20 мкм) на фізико-механічні властивості сплаву Co-Cr-Mo виготовлених методом селективного лазерного плавлення.Матеріали й методи. Всі дослідні зразки було виготовлено з порошку Co-Cr-Mo сплаву з розміром частинок від 10 до 45 мкм. Друк зразків при товщинах шару 20 та 40 мкм проводився на 3D принтері Alfa-150 виробництва компанії ТОВ «АЛТ Україна». Розташовувалися зразки для випробуваньна розтягування на платформі в горизонтальному(осі X та Y) і вертикальному положенні (вісь Z). Випробування для визначення механічних властивостей проводили відповідно до ISO 6892:2019 на випробувальній машині «PHYWE». Коефіцієнт температурного розширення визначали за допомогою дилатометру DIL.A.802.Результати. Встановлено залежність щільності металу при постійній товщині нанесеного шару 40 та 20 мкм тавідстані між треками 0,1—0,12 мм та обрано раціональні режими для виготовлення зразків на розтягування.Висновки. З’ясовано, що зменшення міжтрекової відстані сприяє досягненню щільності 99,99% та збільшенню області раціональних режимів друку. Показано, що зразки, надруковані при різній товщині робочого шару, мають різні значення механічних властивостей. При порівнянні зразків, побудованих при різній товщині шару та в однаковому напрямку, з’ясовано, що значення тимчасового опор має найнижчі значення для вертикальних зразків порівняно з горизонтальними в напрямах Х та Y.

The purpose of the work is to study the microstructure and mechanical properties of 316L stainless steel samples made by the SLM method. 316L stainless steel has been extensively studied for the state after fabrication by selective laser melting (SLM). This is due to the wide use of this material in various industries, as it demonstrates sufficient corrosion resistance and excellent plasticity. Thus, its application can be found in the biomedical, aerospace, automotive and marine fields. Some of the studies conducted have shown the ability of SLM to improve the mechanical properties of parts compared to traditional methods. Metallographic analysis, determination of mechanical properties, and chemical analysis were used. The object of the study was austenitic grade 316L stainless steel. The material for making the samples was a 316L alloy powder with a particle size of 45 + 15 μm. Experimental samples for tensile tests were built on the equipment of "Additive Laser Technologies of Ukraine" LLC (Alfa-150) using SLM technology in identical modes: laser power - 290 W, scanning speed - 1100 mm/s, distance between tracks – 0.11 mm, scanning strategy - checkerboard fields, scanning order - Zig-Zag, field size - 5 mm, rotation of the layer relative to the previous one - 67°. From the results of the analysis of mechanical properties, it was established that the samples made on the 3-D printer of Additive Laser Technologies of Ukraine LLC are not inferior in terms of quality to leading global companies, and in some characteristics even exceed them. It should be noted that the results of determining the characteristics of the experimental samples were compared with the properties of the samples manufactured according to the optimal process parameters on the equipment of different manufacturers, but do not include the influence of the thickness of the applied layer. Comprehensive studies of the mechanical properties of the samples made of 316L steel showed full compliance with the samples produced on the equipment presented on the world market for the production of special-purpose products.

SLM technology is an innovative production of products of complex geometric shapes through layer-by-layer material building-up based on a computer-based CAD model using special 3D printers. With the help of SLM technology, they create precise metal products for work as part of components and assemblies for critical purposes (for example, aerospace). SLM successfully replaces traditional manufacturing methods, since products built using SLM technology often surpass the properties of products made using traditional technologies.This technology has several advantages for the application and manufacture of aerospace products: the possible production of thin-walled parts, simplifying their production, by reducing the number of technological transitions, using computer programs and automation tools to optimize the product design, which opens up the possibility of reducing the weight of aircraft structural elements apparatuses.One of the opportunities that SLM technology allows to realize is the replacement of solid metal elements with openwork structures, ensuring a sufficient level of mechanical properties. The use of openwork designs and topological optimization can make it possible to lighten a part up to 50 %. However, it is important to ensure the necessary level of mechanical properties due to the reasonable design of elements: mesh thickness, cell size, and shape, etc. Besides, in aircraft and rocket science, often additive technologies are used to create products with internal channels of thin-walled products with inclined surfaces. Therefore, it is important to ensure the quality of thin-walled surfaces with different angles of inclination.Printing was carried out on a 3-D Alfa-150 printer manufactured by ALT Ukraine LLC. As part of the experiment, samples were made in the form of a cube with the internal structure of the honeycomb and a solid cube with equal dimensions in different modes. The second group of samples in the form of plates with different angles of inclination relative to the Z-axis (0°, 30°, 45°).When practicing printing modes with internal thin structures, it was found that under adverse conditions, fusion conditions were created, the metal fell through on a layer of powder, overhanging elements formed, and the lower surface with high roughness. Under favorable conditions, the lower surface is smooth, the layers are clearly defined, correspond to the given geometry of the model. An experiment was also performed to test the printing modes of flat samples with different angles of inclination. It has been established that different modes are optimal for different tilt angles. Thus, it was found that SLM technology allows you to create thin-section elements with maximum accuracy, and to produce parts with a unique geometric structure. According to the developed process parameters, parts of complex shape for operation in aerospace engineering can be created.

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Additive technologies make it possible to provide high quality products (accuracy and uniqueness of geometry, high complex of mechanical properties, high density (low porosity), uniformity of microstructure and chemical composition). A wide range of materials used allows it to find application in such industries as medical and dental, engineering, automotive and aerospace. At present, technological capabilities, the development of laser technologies and CAD modeling systems have made it possible to develop devices for building parts by loading the original CAD model and fusing metal powder using a laser in accordance with it – what is today called SLM technology. During this process, the metal powder is completely melted under the influence of high-power laser radiation with the formation of a metal layer that contains almost no pores and does not require further processing, which makes it possible to achieve a level of mechanical properties of the product equal to or even better than those of cast ones. To create advanced equipment and professional control of the process of manufacturing parts, a deep understanding of the processes occurring in the melt pool under the laser beam and after hardening is necessary. At the same time, the final quality of products manufactured using SLM technology depends on many factors that can be divided into main groups: equipment (calibration, laser power, energy distribution in the beam, powder application system, shielding gas supply, distribution and purification system, system ensuring the tightness of the chamber, etc.), material (sphericity, dispersion, bulk density, fluidity, properties, handling, etc. of metal powder), process parameters, geometry features of the part, finishing. Prospects for the development of technology in Ukraine are associated with the development of new structural materials, solving topology optimization problems, prototyping, studying the properties of materials and creating the latest production solutions in the field of additive technologies.