Nº 7 (169) (2025)
Technologies of electromachining and combined processing
ULTRASONIC APPLICATION FOR SURFACE LAYER MODIFYING IN PARTS PRODUCED BY ADDITIVE TECHNOLOGIES
Resumo
A number of works devoted to the technological heredity of products obtained by additive technologies are analyzed. One of the main disadvantages of additive manufacturing methods for plastic and metal objects is the high surface roughness caused by the layering technique. Based on the analysis of the sources, the directions of development of ultrasonic post-treatment of products have been determined. It can significantly reduce surface roughness. Studies have been conducted on the finishing of plastic products in a solvent evaporation obtained by ultrasonic spraying. The technique makes it possible to adjust the size of the droplets and the speed of their movement by changing the modes of ultrasonic treatment. Evaporating treatment schemes for products of different sizes are proposed. As a result of experimental studies, it has been established that evaporating treatment of a solvent obtained by ultrasonic spraying allows significant reduction of the surface roughness. Various types of ultrasonic treatment have been proposed for parts obtained by selective laser melting to improve the surface quality of products. Comparative studies have been conducted on the effects of cavitation-erosion and cavitation-abrasive treatment, as well as ultrasonic surface plastic deformation aimed at reducing surface roughness. It was revealed that all mentioned types of ultrasonic treatment contribute to surface roughness decrease in the following ways: cavitation-erosion by 33 %, cavitation-abrasive by 43 %, ultrasonic surface plastic deformation by 52 %.
Science intensive technologies in mechanical engineering. 2025;(7 (169)):3-12
3-12
PHYSICO-TECHNOLOGICAL FOUNDATIONS OF INCREASING THE DURABILITY OF DIE TOOLS BY HARDENING WITH HIGH-ENERGY FLOWS
Resumo
The issues of the formation of equilibrium conditions in ordered dislocation structures obtained by the action of highly concentrated electric energy fluxes and an informal (longitudinal-torsional) ultrasonic field on a conductive substrate material are viewed. The effect of solid surface films on deformation and fracture, being used as barriers and capable of suppressing the occurrence of new dislocations during metal deformation processes, is shown. The factors that determine to a greater extent the effectiveness of the film in creating a barrier for dislocations have been identified. A simplified analytical model of the interaction of a single dislocation with the layers obtained by the combined hardening method and the conditions for the equilibrium of dislocations in a film of a given thickness are proposed. The results of experimental studies of a hardened layer formed by anodizing with tungsten and copper on grade 20 steel are presented. They have shown that an increase in product strength occurs under conditions when the shear modulus of the base crystal is less than the shear modulus of the sawn layer, and the action force from this layer tends to push the dislocation away from the phase interface. As a result of the study of electroacoustic spraying effect on the quality and wear resistance of the surface of a die tool, it was confirmed that electroacoustic spraying, realizing a complex effect on metal, improves the quality of tool edges and their strength characteristics, forming a predictable organization of the surface layer structure; a "double barrier" created during electroacoustic spraying on the surface, preventing the release of dislocations on the surface is the main factor in increasing the strength properties of the tool. It was found that the coating applied by the electroacoustic method increases the service life by 1,5 − 2 times if compared to samples where surface was not treated by the above-mentioned method.
Science intensive technologies in mechanical engineering. 2025;(7 (169)):13-22
13-22
Technological processes automated control
CONTROL OF TECHNOLOGICAL INFORMATION AMBIGUITY IN DIGITAL PRODUCTION
Resumo
Based on a meaningful analysis of the concept of "ambiguity" and basic concepts, as well as the tasks of technological design and support of machine-building production, a classification of types of technological information is constructed in accordance with the types and varieties of ambiguity. The types of technological information that most significantly affect the formation of ambiguity of various kinds are identified. The possibilities are substantiated and the information channels providing effective ambiguity control of technological information are described. It is shown that the controlled reduction of ambiguity of the I-st, II-nd and IV-th, in relation to the process and results of metalworking production, can significantly reduce the level of ambiguity of the III-rd kind, these are implications of the decisions, and all this can be described as an equisignificant way to increase the stability of production results.
Science intensive technologies in mechanical engineering. 2025;(7 (169)):23-31
23-31
ALGORITHM OF MANUFACTURING TECHNOLOGY FOR COMPLEX ASSEMBLED PRODUCTS USING DIGITAL MEASURING AND PROCESSING SYSTEMS
Resumo
Modern machine‒building production is being radically reinterpreted and redesigned in technological stages and total restructuring for fundamental improvements in the most important significatives of its activities - cost, quality and productivity. The purpose of the research is to analyze modern methods of reverse engineering, taking into account the continuous development of digital technologies for designing, manufacturing and assembling machine-building products. It is effective algorithmization that can be useful for manufacturing and assembling complex mating parts. The article presents an improved technology for manufacturing and assembling machine-building products using reverse engineering methods. The analysis of successfully solved tasks using reverse engineering in various fields of practical activity is carried out. It is shown that the further development of modern methods of digital design and construction of complex mechanical engineering products and the development of optimal manufacturing technologies requires some rethinking of the goals and objectives. There should be a possibility of using reverse engineering for making effective technologies. For the first time, an algorithm for manufacturing parts of complex assembly products based on the principles of reverse engineering using digital measuring and high-tech processing systems has been proposed. The developed algorithm is protected by the patent application as a method of manufacturing an assembled product. Duplication protection problem in case of competitive machine-building products is analyzed. Various methods of protection against duplication of products obtained through modern techniques of reverse engineering are viewed. The developed method makes it possible to reduce significantly the number of technological operations required for the manufacture of the second part by introducing one control operation for the first part, during which the coupling elements of the first part are measured and a computer model of the second part is created, taking into account the all performed measurements and four machining operations on a CNC machine.
Science intensive technologies in mechanical engineering. 2025;(7 (169)):32-38
32-38
Surface layer quality, contact interaction, friction and wear of machine parts
PHYSICAL-CHEMICAL FACTORS EFFECT ON THE STRUCTURE AND PROPERTIES OF METALS UNDER CONDITIONS OF CONTACT DEFORMATION DURING FRICTION IN A SURFACE-ACTIVE LUBRICATING MEDIUM
Resumo
Based on the concepts of the physical-chemical mechanics of contact interaction, a materials science analysis of these factors effect on the structure and wear resistance of an antifriction alloy under friction in surface-active lubricating media has been carried out. Tests of the bronze BrA5 − steel 45 friction pair were carried out on a reversible sliding friction machine under conditions corresponding to the operating modes of heavily loaded friction units. The role of physical-chemical factors related to the surface activity of the medium was revealed using an experimentally obtained set of macroscopic integral criteria (phenomenal indicators of friction and wear) and microscopic (microstructural) criteria (physical broadening of X-ray lines, the period of the crystal lattice, the elemental composition of the surface layer of the material of the contact deformation zone), determined using the X-ray diffraction method. It is shown that the formation of a wear-resistant structural state of a material in a surface-active lubricating medium is based on two structure-forming processes. The first one is connected with the formation of a stationary macroscopic diffusion flow of atoms of alloying elements and their transition into a lubricating medium, which leads to the creation of a surface plasticized layer, and the second process is a decrease in the density of dislocations in the material of the deformation zone, which indicates the effect of plasticizing the material (reducing its yield point stress). As a result of these processes, the material of the contact zone differs significantly from the initial one in terms of stress state, microstructure, and mechanical properties. The use of lubricants containing surfactants in tribounits contributes to the formation of a wear-resistant structure in the antifriction material.
Science intensive technologies in mechanical engineering. 2025;(7 (169)):39-48
39-48