Industrial robots are used for machining in mechanical engineering. This trend is associated with an increase in the geomet-ric complexity of parts and wider kinematic capabilities of industrial robots in comparison with classical CNC machines. The article analyzes the technological capabilities of using industrial robots in finishing machining operations, and pro-vides the reasons for limited robots introduction Schemes of construction of technological operations are given: "part in hand" and "tool in hand". The factors influencing the choice of the preferred machining are studied. The areas of effective application of passive and active adaptation tools are given. The article provides two main reasons for possible vibrations under robotic manipulation: e.g. low rigidity of the industrial robot structure and shape errors effect in the previous opera-tion. The problem of developing a sustainable code conversion for the amount of material removal is discussed. The problem statement is due to the fact that the model of the cutting process varies greatly depending on the cutting conditions. Force control work makes it possible to take into account the rigidity of the robot without sacrificing the running accuracy in six coordinates. The article discusses the use of a neural network and a genetic algorithm in the development of a robotic pol-ishing operation for a flat surface within limited access constraints. The authors of the article have developed a postproces-sor for controlling an industrial robot in case of variable tool overhang and uneven tolerance. Special technological equipment has been designed and manufactured for this purpose. Experiments on testing of the developed algorithmic and software have been conducted in the laboratory "Industrial Robots and Automation Tools"
the article discusses the problem of technological stability assurance of deep drilling operations performed on automated equipment – multipurpose CNC machines. A group of large-sized forging parts and pressing blanks is viewed. It is shown that using a set of special drills and counterboring tools instead of universal horizontal milling machine makes it possible to avoid making special tools and contributes to the improvement of cutting modes, but the problem of stability assurance re-mains. A study of the hardness of such forgings revealed the unevenness of this characteristic in various parts of the work-piece. Despite the fact that, from the point of view of statistics, the totality of experimental data is homogeneous and the flow process of metallurgical forging production is stable, the revealed hardness variability turns out to be very sensitive for the subsequent stage of machining, namely for its special type like deep drilling. Experimental studies of chip formation in hole-making operations have proved that. It is noted that the task of managing the operability of tools and the quality of the re-sulting surfaces should be solved both at the stage of process design and just within operations. The latter can be solved through adaptive control, which is implemented on modern mass-produced multipurpose CNC machines in terms of the op-erating cutting power, which does not require retrofitting an automated machine-tool fleet for machining sites. The ra-tionale for the selection of factors and their variation levels in the construction of regression models used for design process and adaptive control of deep drilling operations on multipurpose CNC machines is given.
The use of ultrasonic dimensional technologies to reduce technological residual stresses occuring under machining of non-rigid blanks in parts made of alloys with a low melting point is one of the most effective methods for manufacturing structurally complex parts. The main methods of using modulated ultrasonic vibrations (UsV) and their advantages when introduced into the machining zone during milling operations are viewed. Special attention is paid to the use of various types of UsV modulation to increase the efficiency of reducing technological residual stresses by involving dislocation segments of different lengths in the relaxation process when machining thin-walled non-rigid aluminum alloy blanks. The technological residual stresses were evaluated using the Seton-ARM measuring and computing complex. Phase changes in the surface layer of aluminum parts of the Rikor–7 X-ray measuring complex. The data obtained was processed on a computer using the MD-10 program. The UsV modulation was carried out using an original installation that includes a ultrasonic generator, a PC that generates a modulation signal into two channels: on the first channel, a sinusoidal one, on the second, a sinusoidal, square or triangular one with a phase offset of 0 or 90 degrees. Studies measuring the positions of the treated surfaces of thin-walled parts using the Renishaw OMP40 contact sensor have shown that their twisted effect decreases by 30...40%. There was no significant difference in the results of processing workpieces made of deformable aluminum alloys D16 and AK6.
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 %.
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.
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.
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.
High-tech tribotechnologies concept is outlined. Specific examples of the creation of various tribotechnologies are given. The technologies of final treatment of friction surfaces operating under low loads are described. They replace the process of running-in of these friction surfaces, and, consequently, increase the durability of their operation. Technological methods of cylinder liners plateau honing and flat-topped final polishing of bearing journals of sliding bearing shafts are given as an illustration.To increase the durability of bearing rollers, the tech has been developed for their final polishing with closed loop belts. Their width and tension force make it possible to ensure the barrel shape of such rollers, which guarantees an even distribution of pressure along the entire length of the roller. This prevents the possibility of their destruction at the edges unlike in cylindrical shapes.For voyage repair of railway tracks working surfaces a flow process has been developed that ensures the preservation of the rail transverse profile formed during the running-in process in various sections: rectilinear and curved. This tribotechnological process makes it possible to increase the productivity of railway track repairs and their service life greatly. Curved friction surfaces during operation, resulted from different speeds and pressures at different sites when running-in, have different rate of wear, i.e. their optimal crossing profile changes. The above is also true of railroad wheels. Therefore, to increase the durability of the rolling surface of railway wheels, tribotechnology of electromechanical pulse processing has been developed, which ensures uniform wear throughout the profile due to a regular change in the degree of hardening of the wheel profile surface layer.
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.
The paper presents the development of ways to achieve the required quality of promising products in relation to specific products of the aerospace engineering industry. A new selection mechanism for techniques agreed upon in the process of testing the performance for the stable production of high-tech objects of the required quality through the development of a combined controlled technological effect on parts, taking into account their in-service environment. The utility principle has been adopted as the main criterion for a methodology aimed at reasonable selection of technological modes when creating promising handling technique with a combination of various routes of exposure, which allows for a discrete assessment of industrial performance level. It is shown that the value of scientifically justified labor and financial costs of the considered method is used as a boundary condition in modeling processing operations to ensure the performance of high-tech products being created and upgraded at the stages of mechanical engineering mass production, the parameters of which are agreed with the customer and justified by the product developer at the stages of products performance development test. New technological methods and devices are proposed that ensure high efficiency in creating new-generation products using examples of aerospace technology with the required performance. New technological methods and devices at the stage of invention are proposed. They ensure high efficiency in creating new-generation products using examples of aerospace technology with the required performance. An evidence base has been created for the technological services of machine-building enterprises, ensuring that the achieved performance indicators of products are consistent with customer requirements and are confirmed in the process of products performance development test at the stages of their creation, improvement during debugging, mass production and operation.
The technology of grinding bearing parts holds a significant place in machinery production. This topic is particularly relevant at the present time, as there are raised requirements for this process, both in terms of productivity and the quality of finished products. The efficiency of finishing bearing parts in modern high-tech manufacturing is determined by the use of highly efficient abrasive tools with stable performance characteristics. Ceramic-bonded abrasive tools are subject to significant environmental effects, especially when working with water-based cooling lubricants (coolants), which significantly alter the physical and mechanical properties of grinding discs, reducing its hardness and strength and, resulting in a decrease in its performance characteristics. One of the effective ways to improve an abrasive tool can be considered the introduction of solid lubricants (impregnation) into its pores, which improve the grinding conditions and the quality of the surface layer of the machined bearing parts. The laboratory studies carried out by the authors on the basis of the Scientific and Technical Center "VNIIASH" and considered experience of industrial use of impregnated tools in bearing manufacturing enterprises show its effect only in the case of uniform impregnation of the entire abrasive tool and ensuring uniform filling of its pore space. Based on the results of our research, we have found the possibility of productive, high-quality impregnation of abrasive tools with sulfur using the method of free capillary ascent along the pores of the disc. The use of impregnated abrasive tools at the enterprises of the EPC corporation makes it possible to improve the quality of processing bearing parts and reduce the consumption of abrasive tools by 1,1 – 1,8 times.
The technology and the results of its investigation contributing to studying the diversification of the operative conditions of metal cutting tools, are presented as exemplified in a tool equipped with a hard alloy plate. It is shown that the rate of diversification can be judged by the appearance of a two-dimensional histogram constructed from time series of signals indicating fluctuations in the technological system in mutually perpendicular planes. The occurrence of a "comet tail" pattern on the histogram indicates a high rate of diversification of operative conditions, in particular, during the running-in of the tool. To show the dynamics of the diversification, a cross-correlation curve is used, the form of which characterizes the strength of the relationship between the directions of oscillation. This networking proves regulation of operative conditions and the transition to a starting operation in a stationary mode. Diversification dynamics is identified using a procedure based on statistical test of the hypothesis for the significance of changes in the transformation coefficients of the spectra of diverse oscillation signals using the Student's t-test. The identification results showed that state diversification dynamics is a change in connections and constraint in the industrial process system, which leads to the formation of new dynamic properties that reduce cutting forces due to the redistribution of friction forces between the front and rear surfaces of the tool and, as a result, increase stability for disturbance resulted from the operating procedure. The approach used in the development of the process desigh is compared with approaches based on the construction of a mathematical (analytical or stochastic) model of a real system. The direction of practical implementation of the technology in the software of CNC systems is justified for more efficient solution of traditional control tasks, in particular, process tasks, which will ensure an increase in the reliability of the tool.
Economics evaluation method of high-tech technologies application for part process of various purpose made of hard-to-machone steel or alloys at machine-building enterprises is presented. It is shown that the overall economic effect of using high-tech technologies in production processes consists of direct and additional effects. Direct benefits can be obtained by optimizing the modes and changing the conditions of machining parts, increasing the durability of the used metal-cutting tool and improving the manufacturing system as a whole by increasing its reliability and vibration resistance. To achieve direct benefits, it is proposed to use iodine-containing agents in the machining parts processing procedure and metal-cutting tool sharpening, as well as the supply of cooled ionized air both to the contact zone of the tool and the surface of the part. Additive effect can be obtained both by improving the quality of the machined surface of the part, and by perfecting organizational and technological measures during repair work, maintenance and routine maintenance within the operation of mechanical engineering products. The main components of the additive economic effect are viewed and the technique for their determination is given. Based on the analysis of the developed technique for the economics evaluation for high-tech technologies in part process together with its testing at a number of machine-building enterprises, the authors prove that its use provides calculated data comparable to the actual benefits, and can be applied in any type of production, including machine maintenance.
The decade-long period of the evolution starting from the first installations to a modern complex, designed and manufactured entirely using just indigenous content, including software and an optical system, is presented. The first SLM-110 installation, manufactured in 2016, had a construction volume of 110×110×200 mm. Over the years, numerous research projects have been carried out. They served as the basis for the development of technological processes for growing parts and units obtained from various metal powders. In subsequent developments, the volume of grown products was increased to 250×250×300 mm. As a result of the completed R&D, a more advanced SLM-250 installation was designed and manufactured. In this installation with a sensor system a full automatic monitoring and control of process parameters is provided for long-term continuous operation of the complex for many days, ensuring high reliability and stability. A number of plants are successfully used in our industry in the production of complex products from a variety of metal, ceramic and composite powders produced in our country. The next stage in the development of additive manufacturing is the organization of sites for the manufacture of parts based on additive complexes and peripheral equipment. It is necessary to organize serial production of existing installations in our country and develop equipment to increase the process performance
Additive technologies exemplified well in the industry. As a rule, it is technologies called synthesis on a support material (selective laser melting and the like), that make it possible to create products with complex geometries, internal channels, etc Modern software allows significant expansion in the capabilities of such technologies. One of the directions of the development in this area is the generative artificial intelligence, for example, in case of topological optimization aimed at reducing the weight of the product without loss of strength characteristics. It is based on well-known mathematical models and numerical calculation methods. At the same time, it has now become possible to calculate several models in parallel, depending on the set parameters. At the moment, several algorithms are used for modeling and calculations, gaining the reputation of good results, but at the same time an additional verification of the results obtained before manufacturing, is required. This paper presents the main mathematical models and examines the features for optimization in additive technologies. It discusses examples of model combinations. Using the example of a promising optimization method, the existing limitations and the possibilities of overcoming them are studied. Due to the peculiarities of modeling, one of the tasks is to obtain the results closest to the real ones, therefore, an option for improving the work is proposed, taking into account the real values of experiments. A pattern to understand the specifics of the work of various methods is given, allowing a possible data calculation option depending on the available initial conditions.
A number of works devoted to ultrasonic assembly and disassembly have been analyzed, and their disadvantages have been identified, in particular, lack of attention to the issue of multifactorial nature of the influence on assembly using ultrasound. Based on the analysis of the sources, the factors that can significantly affect the assembly process of threaded fastenings are determined. They are temperature, mass of the assembled fastening, as well as the amplitude of vibrations. The results showed that increasing the mass of the assembled threaded fastening increases the effectiveness of ultrasound application. The results also showed that increasing or decreasing the temperature has virtually no effect on the assembly efficiency, which is confirmed by statistical processing, which shows a small relationship between the response and the factor. At the same time, the use of ultrasound, depending on the temperature, affects the spread of the obtained values within a single point – the values obtained vary in the range of 5 % at average temperatures and in the range of 10% at boundary values. The results of the multifactorial experiment confirmed the nature of the influence of the oscillation amplitude, mass and temperature of the assembled fastening, revealing the importance of the amplitude and mass factors, while the temperature factor can be neglected due to its minor influence. The results of the multifactorial experiment were processed using two different methods, as a result of which similar dependencies were obtained, which, in turn, confirms the high reliability of the obtained results.
The effect of a true viscous lubricant in a radial sliding bearing coated by polymer having a specialized groove on the shaft surface is studied. The developed computational model based on the equations of fluid motion and the equation of continuity allows for a deeper understanding of the dynamics of the lubricating layer and its interaction with the working surfaces. Special attention is paid to the geometric features of the groove, which affect the pressure distribution inside the bearing. The integrated use of a polymer coating and a groove ensures uniform load distribution, which increases the load capacity of the system. Numerical calculations show that the use of a polymer coating reduces friction coefficient and contributes to the efficient operation of the lubricant in turbulent conditions. Experimental validation of the model was carried out under various load conditions and rotational speeds, which made it possible to compare theoretical calculations with experimental results in a high-quality way. The analysis showed a high degree of agreement between calculations and experiment, confirming the reliability of the proposed model. The results obtained prove the necessity of design solutions, such as a combination of polymer coatings and grooves for improved bearing performance.
Problematic issues related to the development, machinability and application of new high-strength ceramic materials are viewed. Such materials possess high hardness comparable to the hardness of abrasive materials. Therefore, it makes difficult to produce such materials using traditional techniques. To solve this problem, we have proposed the modernization of the PP 600F machine with the implementation of combined electro-diamond processing of high-strength ceramic materials with diamond wheels on a binder metal. The modernization provides for the development of special components and structures of a current collector, a cathode for straightening a circle, a circuit for a technological current source and constructive solutions for automatic control of the straightening current. Based on the results of the study, rational cutting modes have been established to guarantee the quality of products made of high-strength composite materials. The experiments were performed with standard techniques using optical and electron microscopy. The tasks were solved taking into account the study of diamond wheels flow density on a metallic binder, as well as forces, power, cutting temperature, defects on the surface of the grinding wheel and the machined product. The solution for controlling the cutting capacity of a grinding wheel and the conditions of their operation in the self-sharpening mode is shown. Based on the stabilization of cutting power, the self-sharpening mode of diamond wheels on a metallic binder and grinding modes are switched on:Vgwh = 35 m/s; Spr = 0.5.1.5 m/min; Spr = 0,5…1,5 m/min; Spop = 0,02…0,05 mm/dv.stroke ipr = 0,2…0,6 A/cm2; itr = 4…6A/cm2. Using the example of grinding zirconium diboride with an A C 6 diamond wheel with a grain size of 125/100 in these modes, it guarantees the absence of micro, macro cracks, and the roughness of the machined surface within 0.2…0.4 microns.
The effect of the coating temperature and the displacement of the spray nozzle on the structural and phase transformations in the coating on 40X steel obtained by cold gas-dynamic spraying of a powder mixture of Cu:Zn: Al2O3=35:35:30 (wt%) has been studied. The phase composition of the coating was identified using the method of local X-ray spectral analysis. It was shown that under gas-dynamic spraying there can be five phases garadually occurring in the coating, being formed as a result of solid state transformations under conditions of high-speed impact contact interaction: α - Cu-Zn solid solution; βʹ - CuZn-based solid solution; γ - Cu5Zn8-based solid solution; ε -CuZn3-based solid solution.; η is a solid solution of Zn-Cu. Under sputtering temperatures of 2700and 3600 C, the alpha - Cu-Zn solid solution phase becomes predominant. Tribotechnical tests of a pair of reversible sliding friction steel 40X (coated) – steel SHX15 in an I-20A oil medium have shown that the coupling has high performance at contact pressures of at least 50 MPa. Deformation, diffusion and frictional mass transfer in the zone of contact interaction lead to the realization of the "classical wearlessness" effect, the distinctive feature of which is the formation of a copper-zinc third body with corundum inclusions and capable of direct and reverse coating transfer, providing protection of the surface layers of the friction pair from destruction High wear resistance of the friction pair contacting materials is achieved due to the frictional mass transfer films.
Buried abrasive tool wear products on the surface of critical titanium alloy products become a fatal defect that can significantly reduce the service life of the unit due to intense abrasive wear of the contacting surfaces and the formation of fatigue cracks. Using the example of single grain cutting, it is shown that as a result of micro-piercing of an abrasive material, metal transport to the contacting surfaces of the grain decreases and wear products are introduced into the treated surface. When grinding with tools made of superhard materials, the possibility of monitoring and controlling this process by X-ray spectral analysis is limited resulting from a significant error in determining small concentrations of light elements. In order to measure the parameters of the wear products transport of an abrasive material, a method based on the analysis of polished surfaces images obtained in backscattered electrons is proposed. Based on the results of the elemental analysis, the composition of the wear products and the measurement errors of the transfer parameters under grinding with silicon carbide and cubic boron nitride (CBN) wheels, namely the number and area of buried particles, were determined. The share of structured crystals of abrasive materials for silicon carbide wheels is 80% and for CBN disks is 70%, including 20% corundum crystals (filler).
