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Постійне посилання зібранняhttps://repository.lntu.edu.ua/handle/123456789/390
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Item type:Наукова стаття, RESEARCH OF TEMPERATURE PROCESSES DURING DRILLING OF HOLES(Lutsk: LNTU, 2025) Polinkevich, Roman; Zubovetska, Natalia; Redko, Rostyslav; Chetverzhuk, Taras; Zaleta, Olga; Valetskyi, BogdanThe paper addresses an axisymmetric thermophysical problem occurring during deep-hole drilling, based on a proposed mathematical model for temperature calculation using the heat source method and the principles of spatial- temporal correspondence and local influence. The dependencies of the thermal process were determined, taking into account the mutual positioning of the cutting tool and the part, the material of the workpiece, the presence of cooling with cutting fluid, cutting conditions, chip removal, and the duration of the drilling operation itself. This is particularly important for deep drilling, where the heat source is continuously displaced. It was established that the calculation of the temperature field in the workpiece depends on the action of a ring- shaped heat source with a uniform heat release intensity distribution. Theoretical analysis showed that the maximum temperature should not exceed 300 °C (without lubricating and cooling fluid) and 180 °C (with lubricating and cooling fluid), respectively. Standard chromel-alumel thermocouples (temperature range −100 °C to +1000 °C) were used for temperature measurement. Deep-hole drilling experiments were performed on parts made of Steel 45 (analogous to C45E and Ck45 according to the EU standard EN 10083-2) with diameters of 10 mm and 20 mm, using special deep-drilling tools. The machining was carried out on a universal lathe model 16K20, modified for deep drilling. The temperature in the tool- workpiece contact zone and the temperature distribution within the workpiece (temperature gradient) were calculated. The adequacy of the proposed mathematical model was confirmed, as the calculated temperature values corresponded well with the experimental data.Item type:Наукова стаття, INVESTIGATION OF CUTTING FORCE DURING BORING OF SCREW NON-RIGID MACHINE PARTS(Lutsk: LNTU, 2023-05-24) Povstyanoy, Oleksandr; Redko, Rostyslav; Polinkevich, Roman; Chetverzhuk, Taras; Zaleta, OlhaIn the work, the peculiarities of boring of screw workpieces are described. The regularities of the processes of boring screw non-rigid parts have been established. The specifics of the design of the equipment for boring screw non-rigid parts and the expediency and prospects of using screw workpieces are substantiated. It is based on theoretical and experimental studies. A theoretical generalization and a new solution to the scientific and technical problem expressed in the development and creation of technological processes for processing non-rigid screw workpieces, are presented. This will make it possible to ensure the expansion of technological capabilities and the improvement of technical and economic parameters. Calculations were carried out using a package of applied statistical programs for processing and analyzing the results of experimental studies for a PC. According to these results, the dependences of the response surfaces of the optimization parameter and the two-dimensional section of the response surfaces were constructed and analyzed for a visual representation of the results of the experimental studies. The dependences of the change in cutting force on feed and cutting depth were constructed and analyzed. The dependences of the optimization parameter, that is, the dependence of the cutting force on the change of one input factor with a constant value of the other two factors, were also substantiated. After carrying out research using the program «Statistika», a two-dimensional section of the response surface of the dependence of the cutting force on the feed and depth of cut and the response surface of the dependence of the cutting force on the feed and depth of cut were constructed. The obtained experimental broken line was built based on the results of the conducted research. Approximation of it was carried out according to known standard methods, while the amount of deviation (mismatch) was determined by the method of least squares.