Різання та інструменти в технологічних системах

Постійне посилання на розділhttps://repository.kpi.kharkov.ua/handle/KhPI-Press/62923

Офіційний сайт http://rits.khpi.edu.ua/

У збірнику публікуються наукові статті, у яких висвітлюються актуальні питання в області механічної обробки сучасних матеріалів із застосуванням високопродуктивних технологій, нових методів та вимірювальних приладів для контролю якості оброблених поверхонь і високоефективних різальних інструментів. Висвітлюються аспекти оптимізації й математичного моделювання на різних етапах технологічного процесу.

Рік заснування: 1966. Періодичність: 2 рази на рік. ISSN 2078-7405 (Print)

Новини

Збірник «Різання та інструменти в технологічних системах» включено до Переліку наукових фахових видань України з технічних наук до категорії «Б» згідно Наказу МОН України №409 від 17.03.2020 р.

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Фільтри

2022 - 20232

Налаштування

ORCID: search.filters.orcid.https://orcid.org/0000-0002-3478-5913Ключове слово: search.filters.subject.фрезерування

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  • Ескіз
    Документ
    Influence of radial depth of cut on initial conditions of oscillations during end-milling of thin-walled parts
    (Національний технічний університет "Харківський політехнічний інститут", 2023) Dyadya, Sergei; Kozlova, Olena; Tryshyn, Pavlo; Brukhno, Eduard; Yakhno, Denys
    Milling is widely used in mechanical engineering and other industries. Optimization of this process can lead to improved quality of machined parts, increased productivity and reduced wear of equipment. The paper investigates an important aspect of the milling process, namely the influence of radial depth of cut on the properties of the tool-part technological system (TS) and the amplitude of vibrations during machining. Vibrations can be a direct cause of reduction of quality and accuracy of machined parts. When the amplitude of vibrations increases, their impact on accuracy becomes critical. The analysis of studies of up and down end-milling with different radial depths of cut in the third speed zone of oscillations shows that with increasing radial depth of cut the cutting time and maximum thickness of the cut layer increases. This affects the length of the cutting surface and the character of the workpiece oscillations during up and down-milling. The length of the cutting surface determines how many waves of accompanying free oscillations of the TS and with what intensity will leave their trace on the cutting surface. In up-milling, the thickness of the cut layer increases with increasing radial depth of cut, while the amplitude of the accompanying free oscillations TS and their period decrease. At down milling the thickness of the cut layer decreases, and the amplitude of accompanying free oscillations of the TS and their period increase. A common characteristic feature of up and down-milling is the shaping of the machined surface in the cutting zone with a small thickness of the cut layer. In up-milling, this area is at the beginning of cutting, when the oscillation conditions are the same for all radial cutting depths. Therefore, the machined surfaces after up-milling with different radial cutting depths have close values of pitch and undulation height. At down-milling with increasing radial depth of cut, the amplitude of accompanying free oscillations of the TS in the profiling zone increases. This leads to an increase in the pitch and height of undulations on the machined surface. When milling in the third speed oscillation zone, it is necessary to select the radial depth of cut so that the cutting time is less than the period of the accompanying free oscillations of the TS. This will avoid undesirable oscillations and improve the quality of machining. The paper provides important results and recommendations for optimizing the milling process, considering the influence of radial depth of cut on TS properties and vibration amplitude. These findings may be useful for professionals working in the field of cutting materials processing to improve the efficiency and quality of production processes.
  • Ескіз
    Документ
    Causec of different waves of machined surfaces after up and down end-milling
    (Національний технічний університет "Харківський політехнічний інститут", 2022) Dyadya, S.; Kozlova, Olena; Karamushka, D.; Kushnir, E.
    In modern industry, among the methods of surface treatment is widely used end-milling. Under certain conditions of its use there are self-oscillations, which significantly affect the quality of the treated surface. Various techniques are used to study this influence, in particular, the comparison of the basic fragments of the oscillogram obtained by cutting with the treated surface. It is established that it is formed by the first and last wave of self-oscillations during up and down milling, respectively. But depending on the direction of feed step and the height of the waviness on it have different meanings. Therefore, it is important to determine the reasons that lead to this result. This paper considers the features of each direction of supply that affect the formation of the treated surface. When superimposing fragments of the oscillogram obtained by up milling, it is seen that the deviation of the first wave of self-oscillations from the position of elastic equilibrium starts from the point of incision of the cutter in the part. Therefore, the pitch of the wave on the treated surface depends on the feed and the number of cuts required to cut the first protrusion on the cutting surface. The paper presents a formula for determining the length of the base of this speech. When using it, the discrepancy between the calculated wave step on the treated surface and the measured one does not exceed 4%. In the case of down milling, the last section with waviness on the cutting surface, which is cut and affects the shape of the treated surface, has a shorter base length than the opposite. This is the first reason why the pitch of the wave in the down milling is smaller than in the up. Also at formation of wave on the processed surface at down milling the feature in the form of shift on a phase of waves of self oscillations on each following cut is observed. This increases the cutting time and the length of the cutting surface. Each subsequent forming depression is shifted towards the treated surface with a decrease in its deviation from the position of elastic equilibrium. However, the phase shift direction is opposite to the feed direction. This is the second reason why the pitch of the wave on the machined surface after the down milling is less than after the up. The calculation of the step of the wave of the treated surface after the down milling according to the results of the study of fragments of oscillograms shows that the error does not exceed 12% compared to the measured one.