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Metalworking № 1 (139)/2024 |
Material cutting Stepanov S. S., Radkevich M. M. Procedure for inter-operational control of precision part dimensional accuracy using measuring system
Peter the Great Saint Petersburg State Polytechnic University, Saint Petersburg, Russia This article discusses a typical technological process for the manufacture of end length measures, the possibility of increasing productivity and dimensional accuracy at finishing finishing operations using a developed automated measuring system. The results of studies confirming the effectiveness of the measuring system and the possibility of its use in the technological process of manufacturing precision parts are presented. The method of inter-operational accuracy control allowed to increase productivity at finishing operations by 4 times and reduce the number of defective parts from 30 to 5%. The purpose of the work: Increasing the productivity of the technological process and the yield of suitable parts at the final finishing operations during the manufacture of end length measures. To achieve the goal of the study, the task was formulated, consisting in the development and implementation in the technological process of an automated measuring system of high accuracy. Keywords: technological process, end length measures, precense parts, measuring system, manufacturing accuracy.
Electrophysical and electrochemical processing methods Novoselov M. V. Justification of jet electrolytic-plasma polishing parameters of complex shape surfaces This article discusses the technological modes and parameters of the jet electrolyte-plasma polishing (jet EPP) method and the features of its use for processing the surfaces of coronary stents. The main purpose of the study is to evaluate the possibility of using jet EPP as a finishing method for coronary stents and to determine the optimal conditions under which a high-quality surface with minimal roughness can be achieved. The work analyzes the optimal process parameters and impulse characteristics. Through microscopic analysis of finished coronary stents, the effectiveness of electrolyte plasma jetting as a finishing method for coronary stents and similar products was demonstrated. Keywords: coronary stent, surface finishing, polishing technology, electrolyte-plasma treatment, electrolytic-plasma polishing. New materials and technology Kulkov A. A., Lytkin D. N. Technological methods for ensuring the safety of the surface layer of structural steels during gas dynamic processing Gas-dynamic surface preparation for factory and repair painting of machine-building products is accompanied by damage to the surface layers of metal and their grinding to small thicknesses, invisible to the naked eye. When measured with special devices, a reduction in the thickness of the metal by an amount of about 70 microns is recorded during each cycle of pre-paint treatment. For load-bearing elements of metal structures, a local reduction in the thickness of the metal can lead to a loss of static and dynamic stability of the entire system and its failure. The article presents the results of a study of the gas-dynamic technology of pre-paint treatment for the depth of invasion of the processed metal. Competent variation of the modes of gas dynamic processing for a particular processed steel allows you to minimize the process of its invasion, ensuring the safety of the entire metal structure in preparation for factory and repair painting. Keywords: pre-painting metal treatment, undulation, matting, gas dynamic method, defective layer.
Kulkov A. A. The influence of gas dynamic treatment modes on the resulting quality of pre-paint preparation of metal The gas-dynamic method of metal processing is a combined effect on the surface of a free abrasive and a thermal jet of heated air. This method provides a more powerful effect on the metal than with classical abrasive blasting. The method allows cleaning and simultaneous thermal degreasing of the surface in one pass. However, the power of the jet can damage the metal and cause the surface to become unusable. Therefore, the paper presents a study of the interaction of the gas-dynamic flow and the processed metal, with a view to forming the quality of the cleaned surface and preventing its spoilage. Keywords: roughness, degree of cleaning, free abrasive treatment, degreasing, surface quality. Tabakov V. P., Lukin A. V., Shtubov N. S. Assessment of cyclic crack resistance of two-element coatings based on niobium nitride The results of studies of the stress state, cyclic crack resistance of single-layer and two-layer coatings based on niobium nitride and the performance of carbide inserts with these coatings are presented. It has been shown that two-layer coatings have higher cyclic crack resistance compared to single-layer ones. The greatest increase in the service life of carbide inserts is provided by two-layer coatings that have greater cyclic crack resistance. Keywords: cyclic crack resistance, coating, niobium nitride, cutting tool, durability period.
Mikhalev O. N., Yanyushkin A. S. Regression modeling of optimum cutting conditions A successful cutting process is a cost-effective combination of productivity and tool life while delivering the required product quality. One of the important factors that ensures a balance between these parameters is finding optimal cutting conditions. This process is difficult to automate due to the difficulty of establishing mathematical relationships between the mutual influence of many processing conditions on cutting conditions. To create a model capable of handling this task, it is proposed to use various machine learning methods, such as random forest and gradient reinforcement. Experiments confirmed the high accuracy of these methods in predicting cutting conditions for turning. The implementation and use of such algorithms can significantly improve the efficiency of using tools and equipment, and thereby contribute to the creation of more efficient and balanced production. Keywords: сutting conditions, tool life, automation of cutting conditions, multiple regression, random forest.
Sutaev M. M., Kochura I. A., Sobolev I. A., Remshev E. Yu. Quality control of welded joints by acoustic emission method The article examines the problems and methods of ensuring the quality of welded joints. The advantages of the AE method in comparison with other methods of non-destructive testing are analyzed. The physical processes occurring during the welding process and the factors contributing to the occurrence of defects are considered. The processes of the emergence of AE signals and the features of their propagation in various environments are studied. Graphs of noise propagation during welding are constructed. The main disadvantages of the acoustic emission method are highlighted, and the methods of their elimination are determined by the prospects for using AE control of welded joints. Keywords: acoustic emission, control of welded joints, quality assurance, welding, defect, crack.
Quality control and measurement technology Kugushev V. I. Theoretical substantiation of the construction of the model of the carrier of free energy of natural oscillations of machine parts and mechanisms The paper considers the problem of excitation of natural vibrations. An attempt to model the processes that occur in the time interval from the impact on the part to the occurrence of natural vibrations in it is presented. The author proceeds from the fact that the known explanation linking the occurrence of natural vibrations with the appearance of standing waves as a result of the addition of direct and reflected travelling waves does not have a concrete physical embodiment, because the impact creates an impulse, not a continuous flow of waves. And so the task was to find an explanation of how the energy concentrated in a single impulse is uniformly distributed throughout the part when natural oscillations occur. It is shown how the proposed model of the carrier of free vibration energy solves this problem. For this purpose, the model uses a broader approach to the consideration of the structure of space, involving Riemannian spaces of constant positive and negative curvature. Justifications are given that if no physical processes occur in these spaces, but only geometrical changes, then Riemannian spaces do not introduce arbitrariness and dynamic process of excitation of oscillations. For practical purposes, the proposed model can be a tool for analysing the influence of various factors, including defects, on the excitation of natural vibrations in non-destructive testing and vibrodiagnostics. Keywords: shock impulse; natural vibrations; Riemann spaces; nondestructive testing. List of articles in the Metalloobrabotka magazine for 2023 |