Papers by Keyword: Cutting

Abstract: The production of high-quality and long-lasting products requires the application of materials with specific properties in their production. Therefore, the share of application of materials with high hardness and strength has been increasing recently. This encourages many researchers to focus their development on materials with specific properties. These materials, which are characterized by specific properties, include sintered carbides. Therefore, research was conducted with the aim of obtaining relevant dependencies of the influence of the chemical composition of sintered carbides with a Co binder on their selected mechanical properties. As part of the research, significant dependencies of the influence of the percentage of the Co bonding element in the sintered carbide as well as the grain size on its hardness, flexural strength and fracture toughness were obtained. It was found that with an increasing proportion of the Co bonding element, hardness decreases and at the same time flexural strength and fracture toughness increase. At the same time, with increasing grain size, hardness and flexural strength decrease, while fracture toughness increases. The obtained data also provide suitable data for optimizing the mechanical properties of sintered carbides and drawing complex conclusions in several important contexts.

Abstract: This study investigated the effects of tool runout on chatter vibration taking images of a machined surface to assess the vibration strength, number of vibrations, and phase difference depending on the spindle speed and axial depth of the cut. This study obtained significant results regarding the stability pocket represented by the spindle speed. We observed that the stability limit changed depending on tool runout.

Abstract: In the powder metallurgy method, after sintering, it is often necessary for the sintered steel machine parts to be machined by the metal removal process for dimensional accuracy. In this case, it is imperative that the tool materials have good wear resistance. Polycrystalline cubic boron nitride compact (cBN) seems to be an effective tool material because it has good heat and wear resistance. In this study, in cutting sintered steel with cBN tools, various cBN tools have been used in cutting experiments to identify an effective combination of binding phase and cBN content. As a result of experimentally examining the wear progress of the CBN tools, a cBN tool having a binder phase of (Al₂O₃-Al) and a cBN content of 60% was effective for wear resistance.

Abstract: The present work proposes to emphasize the effects of friction and wear formulations for wear prediction for turning operations. It is shown that friction models play a major role on local variables such as pressure, sliding speed and temperature (σ_n, V_sl, T) and thus on the simulated tool wear. This work highlights that both formulations and parameters of these equations should be carefully considered to achieve an actual predictive capability.

Abstract: Today, under the conditions of sanctions, the Russian Federation needs more than ever the development of energy-saving technologies in various industries. The greatest impact on the life and operability of hard alloy cutting tools is exerted by the physical and mechanical properties of tool materials. Studies have shown that the physical and mechanical properties of tungsten hard alloys in the process of operation, namely in the process of cutting difficult-to-process materials under the influence of high temperatures, vary symmetrically. This study was based on the laws of physics of the division of electrodynamics, as well as well-known non-destructive testing techniques, scientific foundations of materials science, all studies were carried out in accredited laboratories of Tyumen Industrial University. Results of research on determination of temperature of maximum operability of replaceable cutting hard-alloy plates based on study of change of electromagnetic properties are obtained. On the basis of persistent tests in factory conditions, it was proved that the developed technique allows determining temperature intervals of maximum operability based on the study of changes in electromagnetic properties of hard alloys.

Abstract: To increase the durability of the cutting tool when machining parts in mechanical engineering and engine building, the method of applying a diffusion discrete oxide layer with a polycrystalline structure can be used. By identifying the durability of the cutting tool with the period of its durability, we obtain an expression for the effective molar activation energy. Comparative tests have shown that a cutting tool with a diffusion discrete oxide layer can increase the durability when machining parts in comparison with a tool coated with TiСN, which in turn allows to increase the service life of parts by at least 2 times.

Abstract: In this paper, the problem distortion the end of a cylindrical workpiece in the cutting process on hot shears before being fed to the piercing mill is considered. To solve this problem, a new calibration of knives has been developed, and a finite element model hot cutting shears has been developed using the DEFORM-3D computer simulation software package. Modeling the cutting process using the proposed calibration has been carried out. It was found that the knife calibers geometry plays an important role in the formation end part geometry of the blank. Based on the simulation results, it was concluded that proposed calibration reduces the ovality workpiece end by almost 2 times in comparison with current calibration. Recommendations have been developed for the production of changes in the existing technology for cutting pipe billets.

Abstract: The paper presents the results of numerical experimental studies of cutting titanium blanks using mathematical modeling programs, which make it possible to completely repeat technological processes in a computer (digital twin). The LS-DYNA product was used as a program to simulate the process of stock removal from titanium blank. It has been established that the use of this method adequately describes the cutting processes, including with the introduction of the energy of an ultrasonic field into the processing zone, can significantly reduce the duration of experimental research and evaluate the influence of the elements of the cutting mode and design parameters of the tool on the thermal power aspects of the formation of new surfaces of machine parts.

Abstract: Formation of roughness during treatment by polymer-abrasive brushes occurred as a result of interaction of cutting micro-relief with processed surface. The cutting micro-relief of abrasive instrument is described in the form of random process with normal distributional law. When calculation of roughness, the depths of penetration of cutting lugs in processed material as well as regularity of changing of radial radius of rounding of peaks of cutting lugs from modes of treatment are taken into consideration. Set are relations of roughness of processed edge from modes of treatment (deformations of instrument, cutting velocities, feeding) as well as from constituent cutting force. It is proved that usage of polymer-abrasive brushes for rounding of edges faces all requirements of aviation industry on roughness of processed edges.

Abstract: In this study a novel inverse hybrid experimental-simulative approach to the determination of the thermal tool load as a function of the coating properties during orthogonal turning of AISI4140 with Cr_1-xAl_xN-coated cemented carbide tools is presented. The approach consists of an experimental determination of the internal tool temperatures by means of fiber-optic pyrometry as input for an inverse FEM-based simulation algorithm to calculate the surface temperatures. Based on a parameter study, the coating thickness s and the thermal conductivity of the coating λ_c were identified as the main factors influencing the thermal tool load. The combined influence of these properties was described via the thermal resistance R. It could be shown that the average thermal load on the tool surface increases with increasing thermal resistance R.