2021 № 94 Різання та інструменти в технологічних системах
Постійне посилання колекціїhttps://repository.kpi.kharkov.ua/handle/KhPI-Press/77628
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Документ Influence of the geometric characteristics of the discontinuous profile working surfaces of abrasive wheels for precision and temperature when grinding(Національний технічний університет "Харківський політехнічний інститут", 2021) Yakimov, A.; Bovnegra, L.; Tonkonogyi, V.; Vaysman, V. O.; Strelbitskyi, V.; Sinko, I.Grinding is the most common finishing method for hardened steel parts. Grinding is accompanied by a large heat release in the cutting area, under the influence of which structural changes appear in the thin surface of the processed parts, tensile stress and even microcracks, which significantly reduce the operational reliability of machines that include these parts. The use of abrasive wheels with an intermittent working surface makes it possible to reduce the temperature in the area of contact of abrasive grains with the material of the workpiece and, as a consequence, stabilize the quality of the surface layer of the workpieces. High-frequency vibrations in the elastic system of the machine, accompanying the work of an intermittent wheel, are a positive factor that reduces the energy consumption of the grinding process. However, under certain conditions of dynamic interaction of the tool with the workpiece, parametric resonance may occur, which worsens the geometric and physical-mechanical parameters of the quality of the surface layer of the processed part. The aim of the work is to realize the possibility of predicting the quality parameters of the surface layer of parts during intermittent grinding by studying the influence of the design features of the macrotopography of the working surface of abrasive wheels and processing modes on the nature of the dynamic interaction of the tool with the workpiece and the heat stress in the cutting area. It was found that the parametric vibrations of the elastic system of the machine tool can be shifted to a more stable area, due to an increase in the number of interruptions of the working surface of the abrasive whee l with a constant ratio of the length of the protrusions and depressions. The increase in the number of breaks on the wheel also contributes to a decrease in temperature in the cutting area. It was found that to maintain the stable operation of the elastic system of the machine, it is necessary to reduce the number of cavities on the grinding wheel with an increase in the cutting speed. However, both of these actions are accompanied by an increase in the heat stress of the grinding process. It has been experimentally established that for ordinary (pendulum) grinding, it is possible to achieve an increase in processing productivity by increasing the speed of the longitudinal movement of the table.Документ Investigation of the effect of areal roughness measurement length on face milled surface topographies(Національний технічний університет "Харківський політехнічний інститут", 2021) Nagy, AntalSurface roughness is of great importance in the manufacturing industry, as it affects surfaces’ tribological properties (wear, friction, lubrication, etc.), corrosion resistance, fatigue strength and appearance. Areal roughness measurement, which provides a more comprehensive characterization of surfaces, is becoming increasingly popular, but systematic studies are still lacking, so measurements are often analyzed differently. In this paper, the effect of the measurement length is analyzed in the main measurement direction on areal roughness of face milled surface topographies, which were measured with a confocal chromatic sensor.Документ Finish machining of the cutting inserts from cubic borine nitride BL group composite(Національний технічний університет "Харківський політехнічний інститут", 2021) Chumak, A.; Klimenko, S.; Klimenko, S.; Manokhin, A.; Naydenko, A.; Kopeikina, M.; Burikin, V.; Bondarenko, M.; Burlakov, V.Finishing methods of machining of superhard composite’s working elements based on cubic boron nitride BL group are considered. The results of the microgeometry formation research of the cutting inserts’ surfaces during machining by free powders of synthetic diamond, grinding wheels and a method of vibro-magnetic-abrasive machining (VMAM) are presented. It is shown that during VMAM the friction between the inserts’ surfaces and the abrasive particles result in microremoval of the material, which reduces the roughness of the cutting inserts’ surfaces. It is established that additional fine grinding with 14/10 mkm synthetic diamond powder provides the absence of microgeometry defects of the cutting inserts’ surfaces left by pre-machining. The result of high-quality rounding of cutting edges and the formation of surfaces of cutting inserts with less roughness is an increase in strength and wear resistance of metal-cutting tools in high-speed machining under conditions of significant loads.