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Документ Theoretical value and experimental study of arithmetic mean deviation in rotational turning(Національний технічний університет "Харківський політехнічний інститут", 2022) Sztankovics, István; Kundrak, JanosThe calculation method of the Arithmetic Mean Deviation (Ra) is presented for rotational turning. The necessary equations for the calculation of Ra are given beginning from the equation of the cut surface theoretical profile, and we determine the theoretical values in the studied range of the technological parameters. Cutting experiments with these data were performed and the roughness values of the machined surfaces were measured. Then we carried out a comparative analysis of the measured and the calculated values ofthe arithmetic mean deviation.Документ Decision support method for the applicability of hard turning(Національний технічний університет "Харківський політехнічний інститут", 2022) Kundrak, Janos; Deszpoth, Istvan; Molnar, ViktorIn this study the applicability of hard turning is analyzed in the case of disc-shaped parts (gear wheels). The relevance of such parts has been increasing in the automotive industry; therefore, the efficiency of large series or mass production has high priority. The novelty of this paper is the collection of factors that has to be considered in preparation for applicability decisions of hard turning in order to ensure efficient machining. This can be the basis of the IT support, i.e. an automation solution for technologists. The introduced process is elaborated on the basis of theoretical considerations and production shop-floor experience.Документ Analysis of the change in roughness on a face-milled surface measured every 45° direction to the feed(Національний технічний університет "Харківський політехнічний інститут", 2021) Nagy, Antal; Kundrak, JanosIn this article, we analyze the difference (inhomogeneity) of the roughness values measured on a nonalloy carbon steel surface milled with a parallelogram-shaped (κr = 90°) insert as a function of the the tool movement direction and the relative position of the examining points on the workpiece surface. The characteristic distribution of roughness and the magnitude of the deviations were examined by measuring at selected points along several planes on a surface characterized by the movement conditions of the workpiece and the symmetrically arranged tool perpendicular to the machined surface, which formed double milling marks. The selected points mark the lines with specified inclinations with respect to the feed direction, and their measured values were compared. In these directions, the magnitude of the difference in roughness measures was obtained.Документ Lead time reduction in manufacturing process of toothed parts(Національний технічний університет "Харківський політехнічний інститут", 2019) Molnar, Viktor; Deszpoth, Istvan; Kundrak, JanosIn manufacturing automotive industrial components, the reduction of machining time and operation spare time detected in the cutting operations can be realized by the modification of technological parameters. However, reduction in the total component manufacturing lead time can be realized to a great extent by re-organization of the production process to eliminate unnecessary waiting periods (e.g. storage, in-process storage, etc.). In our study the total lead times of two different types of components were analyzed by mapping the process in a detailed way. The rate of waiting time within the lead time was analyzed; the theoretical and the measured lead times were compared and the effect of operation sequence on lead time was analyzed. Using these calculations and also measurements the problematic operations were identified and suggestions for process improvement were made.Документ Face milling with a round insert at various cutting speeds and feed rates(Національний технічний університет "Харківський політехнічний інститут", 2019) Makkai, Tamas; Kundrak, Janos; Karkalos, Nikolaos E.; Markopoulos, Angelos P.Face milling is frequently used for the rendering of flat surfaces with a high degree of precision. With this machining process, high material removal rate is possible to be attained but management of cutting forces values is also desirable, in order to avoid excessive power consumption, tool wear or vibrations. This can be achieved by selecting the process parameters within an appropriate range for each case. In the present study, an experimental investigation is conducted with a view to determine the effect of two important process parameters, namely cutting speed and feed on the cutting forces and the specific cutting forces during face milling, in cases where a round insert is used.Документ Investigation of surface roughness on face milled parts with round insert in planes parallel to the feed at various cutting speeds(Національний технічний університет "Харківський політехнічний інститут", 2019) Kundrak, Janos; Nagy, Antal; Markopoulos, Angelos P.; Karkalos, Nikolaos E.In this paper, the roughness of the surface produced by symmetrical face milling is examined. During the research work, the effect of the use of a round milling insert on the surface topography was studied at different cutting speeds. 2D and 3D surface roughness measurements were carried out in three measurement planes parallel to the feed direction, one of them being the plane of symmetry and the other two planes being at the same distance from it, in both sides. From the analysis of results, it was found that surface roughness decreases significantly for cutting speed values over 100 m/min and then its variation is minimal. Furthermore, higher values of surface roughness are observed in the symmetric plane than the other parallel planes and almost in every case, surface roughness was found to be larger on the entry side plane than the exit side plane.Документ Comparative analysis of CBN cutting inserts with different edge geometries(Національний технічний університет "Харківський політехнічний інститут", 2019) Kundrak, Janos; Sztankovics, Istvan; Gevai, MartinaIn this paper the experimental results of newly developed cutting inserts with special geometry and position for machining of hardened surfaces are summarized. The design of the tool holder and cutting insert allows the increase of the applied feed values in hard turning. Experiments are carried out at increased feed in bore turning procedure and the results are compared with the nowadays used conventional turning technology.Документ Investigation of the effect of depth of cut and cutting speed on cutting forces during face milling of steel with a rectangular cutting insert(Національний технічний університет "Харківський політехнічний інститут", 2019) Karkalos, Nikolaos E.; Markopoulos, Angelos P.; Makkai, Tamas; Kundrak, JanosIn metal machining processes, the achievement of a sufficiently high material removal rate is desirable. Material removal rate can be increased to the desired value by an increase of feed rate value and also by increase of cutting speed or depth of cut values. However, as it is also required that surface quality and deformation should be within the acceptable limits, it is necessary to control them by selecting the appropriate process parameters values. In this study, face milling experiments are conducted in order to investigate the effect of using different values of depth of cut and cutting speed on the cutting forces and specific cutting forces. A comparison between the experimental results from cases with constant feed rate and two different depths of cut at four different cutting speed values, ranging from 100 to 400 m/min is conducted. After the subsequent analysis of the results, conclusions on the effect of depth of cut and cutting speed on cutting forces and specific cutting forces are drawn.Документ Influence of depth of cut and cutting speed on cutting forces in face milling under constant chip cross-section conditions(Національний технічний університет "Харківський політехнічний інститут", 2019) Karkalos, Nikolaos E.; Markopoulos, Angelos P.; Makkai, Tamas; Kundrak, JanosIn various high-end industries such as the automotive and the aerospace industry, face milling is one of the most preferred solutions for the fabrication of flat surfaces with high quality. During machining it is desired to achieve the required result with high efficiency. However, attention should be paid so that forces are kept within acceptable limits for maintaining energy consumption and loading of machine tool at relatively low levels. Thus, it is important to determine the influence of process conditions, such as depth of cut or cutting speed, on cutting forces. In this study, this is attempted by conducting experiments at two different depths of cut and four different cutting speeds for cases with the same chip cross-section value. After analysis of obtained results, useful conclusions on the influence of these parameters on cutting forces are presented.Документ Investigation of surface roughness characteristics of face milling(Національний технічний університет "Харківський політехнічний інститут", 2019) Nagy, Antal; Kundrak, JanosSurface quality and accuracy affect the integrity and lifetime of machine parts and the operational requirements of the structural (or assembly) units. These are the reasons that the expected surface roughness must be planned based on the operational requirements of the parts. The path of the tool edge, which is defined by the characteristics of the kinematics of face milling, makes the milled surface inhomogeneous, which means the roughness analysis in various directions gives different values. In this paper the effect of increasing the feed rate on surface roughness is investigated. This cutting data is chosen because increasing the feed rate is an effective way to increase productivity.