Papers by Keyword: Tool

Abstract: In the work, the design of the tool – boring bar for parallel machining of conical surfaces and threads in coupling-type parts with opposite directions, same inclination, coaxial conical surfaces and threads is given, and their generalized design features are presented for the machining of couplings of different types and sizes. With the application of the designed tool - boring bar to machining of inner surfaces of couplings, their machining accuracy, especially accuracy of coaxiality of threads, thus the load-carrying capacity of the couplings increases, the technological cost of their production is reduced, and the efficiency of their use is ensured.

Abstract: The article describes the design and purpose of a turbopump unit, in particular, the pump body of the liquid rocket engine turbopump unit. The technology and technological equipment for obtaining complex profile holes in the turbopump units body are presented. The design features of technological process and equipment for electrochemical processing are considered. The proposed technology and devices allows to process parts of the liquid rocket engine turbopump unit with special holes.

Abstract: The paper provides an assessment of the safety processes of high-modulus energy sources systems during the initiation of flat and cylindrical high-modulus energy sources. The expressions, which establish the relationship between the parameters of flat and hollow cylindrical charges of explosives under the only condition of equality of the developed pressure pulse on the surface of the charge of explosives, provided all other things being equal, were obtained. In contrast to the earlier studies, which assert the existence of a direct relationship between the parameters during the initiation of flat and cylindrical surfaces, the current study demonstrates energy consumption during the initiation of cylindrical surfaces is higher than the initiation of flat surfaces, all other things being equal.

Abstract: The paper presents the results of experimental development of the technology of friction stir welding to obtain a nonseparable connection of a special aerospace aluminum, titanium and magnesium alloys, high-temperature steels. Regularities and models of heat balance in the welding zone have been determined, which make it possible to predict the technological possibilities of high-speed friction welding. It is established that high-speed friction welding by mixing allows to obtain a high-quality connection at lower loads on the design of the equipment. On the basis of studies of macro-and microstructure, microhardness, level of residual stresses and strength tests, technological recommendations on the choice of welding conditions and conditions were obtained. Presented of experimental and industrial development of special equipment, high-speed friction welding, design and manufacturing of high hardness tools of complex spatial shapes for welding aircraft materials.

Abstract: During the dry machining operation, the cutting tool is constantly subjected to extreme conditions in terms of thermal and mechanical stresses at the tool-chip interface. Indeed, the high temperature and the large plastic deformation affect and particularly accelerate the degradation of the state of the coating of the cutting tool. Thus, it becomes essential to predict the initiation and propagation of a crack in a coated tool. This makes it possible to optimize the cutting and loading conditions in order to improve the efficiency of the coating used and consequently the service life of the cutting tools.In this work, a finite element calculation code "ABAQUS / STANDARD" was used to study and analyze the cracking of a diamond-coated cutting tool. In this sense, we proposed to combine two methods often used to study the discontinuity at the tool-chip and coating-substrate interface. These are respectively the extended finite element method (XFEM) method and the cohesive element method. In addition, a parametric study on the impact of beak radius on cracking was performed to optimize this parameter.

Abstract: Maintenance is a system-specific activity that the purpose of which is to maintain or to increase time, performance and quality of machines and equipment use. The demand for technological equipment is still rising, resulting in often complicated and lengthy repairs. It is necessary to analyze the tools used in the construction of assembly joints and to describe the deficiencies that may occur during assembly. When contacting a material tool using a particular technology and assembly, it is necessary to analyze the impact on the final surface quality of the material.

Abstract: Modern developments in the automotive sector are motivated by the objective of lowering the emission of pollutants. In contrast, growing demands for safety and comfort lead to a potential increase of the weight of vehicles. Thus, the consequent use of lightweight design is indispensable. This includes the use of different materials for the construction of car bodies. Because of various material properties, joining of dissimilar materials is challenging and requires often the application of non-thermic processes like riveting or clinching. These processes are limited by the mechanical properties of the joining partners. Especially the increasing use of ultra-high strength alloys, like the hot stamped steel 22MnB5, makes the development of new joining technologies necessary. One of these innovative technologies is shear-clinching. By combining shear-cutting and clinching in one process, this technology produces durable and tight connections of dissimilar materials with high differences regarding strength and formability. In contrast to shear-cutting the die-sided material has no contact with the punch. Since the process of shear-clinching is a combination of cutting and joining using the same tool, the tool loads differ from common shear-cutting. Especially cutting hot stamped steels is a challenge due to their high ultimate strength which leads to high tool loads. Thus, the analysis of the load condition is essential for the dimensioning of durable and wear resistant tools. Hence, the scope of this paper is a numerical investigation of the tool loads during the indirect cutting process and the subsequent step of joining by forming during shear-clinching. Since an experimental investigation of the occurring tool loads in the closed process is not practicable, the finite element method has to be used. Therefore, a damage-based numerical model is set up to enable the coupled simulation of the combined cutting and joining process and the resulting tool loads. This allows the analysis of the loads during the whole process, identifying the influences of materials and sheet thicknesses.

Abstract: To numerically solve a problem of stress-strain state of a workpiece metal under roll forming, finite element analysis was used that allowed using the principle of elastic-plastic deformations with a multilinear hardening curve. Numerical results of base metal lift have been analyzed and the adhesion strength of antifriction coatings and a steel base has been determined. Some recommendations have been made on optimal diameter choice of a workpiece subjected to the skew mesh roll forming

Abstract: The hyper productive surface plastic deformation processing technology called as wide burnishing (WB) was developed in Russian Federation. The mechanics of new WB technology is different from the classic SPD technologies (rolling or burnishing). For example applied force during processing of burnishing is 150-300 N, of WB is 2500-5000 N due to condition of process implementation in mass production with limited processing time (3-4 turnovers of workpiece). WB also has a high degree of deformation due to a multiple deformation passes. The requirement to develop the methodology for testing “Gland neck parts of the car LADA processed by various methods” was caused by the fact that the previously carried out bench tests do not reproduce the real surface of necks shafts working in pair with lip seals. As well there was no methodology for measuring the value of the gland neck wear and the maximum value of the wear grooves was defined of 1.0 mm. Specimens reproducing gland neck in two of the most critical parts were tested: flange of cardan shaft mounting to the drive shaft of the gear box made of steel 40 and crankshaft made of high-strength cast iron 75-50-03 of LADA car. Test results of specimens made of steel 40 presented the surface roughness parameter Ra = 0.06 microns after burnishing and Ra = 0.28 microns after polishing. The test results were measured on profilograph and were obtained the following data: the width of the grooves wear was 936 microns with burnishing and 1152 microns with polishing, depth was 2.16 and 4.94 microns respectively. Size of cross-sectional area of specimen’s groove wear with burnishing - 1090 um², with polishing - 2848 um².

Abstract: The hyper productive surface plastic deformation processing technology called as wide burnishing (WB) was developed in Russian Federation. The mechanics of new WB technology is different from the classic SPD technologies (rolling or burnishing). For example applied force during processing of burnishing is 150-300 N, of WB is 2500-5000 N due to condition of process implementation in mass production with limited processing time (3-4 turnovers of workpiece). WB also has a high degree of deformation due to a multiple deformation passes. To determine the optimal WB processing parameters single and double instrumental devices were implemented and tested. Specimens made of steel 40 and high-strength cast iron 75-50-03 were tested. Initial roughness of steel 40 specimen’s surface was Ra = 0.5 microns and high-strength cast iron was Ra = 0.85 microns. Results of surface texture parameters of processed parts such as surface roughness Ra of steel 40 and high-strength cast iron 75-50-03 under varying load values P and number of cycles (the number of workpieces revolutions during the period of burnishing) were acquired. It was established that the minimum Ra value of the processed surface correspond with values of P = 210 N/mm² for steel 40 and P = 410 N/mm² for high-strength cast iron 75-50-03 regardless of number of burnishing cycles. Plastic deformation mechanism (processing time and pressure on the surface) influences on the processed surface roughness formation. It is possible to assume that straining state forms at the optimal values of P in terms of achieving a minimum value of Ra in which the reached degree of hardening allows to minimize the height of the microscopic irregularities of the previous grinding processing. In this case there is no plastic flow of the metal surface layer.