2023 № 99 Різання та інструменти в технологічних системах
Постійне посилання колекціїhttps://repository.kpi.kharkov.ua/handle/KhPI-Press/71408
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Документ Probabilistic approach to calculating the rational thickness of the tool's cutting insert for heavy machine tools(Національний технічний університет "Харківський політехнічний інститут", 2023) Klymenko, Galyna; Kovalov, Viktor; Vasylchenko, Yana; Korchma, Dmytro; Boroday, RomanThe paper proves that the development of regulations for the operation of cutting tools on heavy machine tools, the formation of objective functions for optimising the parameters of machiningparts should be carried out based on a given level of reliability of the cutting tool. In this case, a large number of indicators are used to determine the tool's reliability, durability and maintainability separately. Based on statistical and theoretical studies of the probabilistic nature of the properties of the cutting tool and the parameter of load distribution on it, quantitative dependencies between the parameters of the scattering of properties and the thickness of the tool plate of a prefabricated tool were obtained. Thestochastic nature of the machining process on heavy machine tools causes a large dispersion of the properties of the machined and tool materials and other machining parameters. This leads to the need for a probabilistic approach to determining the design and technological parameters of the cutting tool. The reliability of a prefabricated cutter depends on both its load and the bearing capacity of the tool structure, which is the ultimate stress that characterises the strength of the structure. Using a probabilistic approach to calculating the thickness of the cutting plate of the cutters, a correction factor for the thickness was determined taking into account the level of reliability of the tool. The level of reliability was understood as the probability that the maximum stress arising under the action of the load will not exceed the bearing capacity. Typical structures that are most commonly used at modern heavy engineering enterprises were investigated. The law of distribution of cutting forces was determined on the basis of statistical data on the operation of carbide cutters. The thickness of the cutting element was calculated for the Rayleigh load distribution law, determined on the basis of statistical data on cutting forces during turning for different cutter designs. The distribution of the bearing capacity of the tool material of the tool inserts was determined on the basis of laboratory tests.Документ Actual contact area on the worn clearance face of the cutter with the round kyborite insert(Національний технічний університет "Харківський політехнічний інститут", 2023) Manovytsky, Olersandr; Klymenko, Sergii; Klymenko, Serhii; Kopeikina, MarynaFor a tool equipped with a circular cutting insert, a dependence is proposed for calculating the nominal area of the contact area on the back surface. It is proved that the actual area of the contact area of the tool differs significantly from the nominal one due to the presence of a system of micro-irregularities, which makes a difference in the assessment of machining process parameters. Using the example of a tool equipped with a circular cutting insert made of polycrystalline cubic boron nitride ciborite, an approach to determining the actual contact area of the back surface with the workpiece during finishing turning of hardened steel is considered. The possibility of taking into account the influence of the system of irregularities in the contact area, determined by the parameters of its topography, on the size of the actual area is shown, and the ratio of the actual and nominal areas of the contact areas of the tool is determined, and it is found that, depending on the degree of development of the microrelief, the ratio of the actual and nominal areas of the contact surface of the cutter differs by at least 20%. It is shown that the actual contact area is also related to the total length of the main and auxiliary cutting edges, determined by the maximum values of the main and auxiliary angles in the cutter plan, and the size of the wear chamfer on the back surface of the cutter.