Ukrainian Journal of Mechanical Engineering and Materials Science
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Item Research on the characteristics of gear-cutting processes for external and internal meshing using the power skiving method(Видавництво Львівської політехніки, 2023-02-28) Hrytsay, Ihor; Slipchuk, Andrii; Bembenek, Michal; Lviv Polytechnic National University; AGH University of KrakowThe results of modelling and investigation of external and internal gear-cutting processes using the power skiving method are presented. The principles of constructing a geometric model of undistorted chip formation are described, based on parameters from which cutting forces are calculated. It is found that, under identical conditions, the cutting force is three times greater when internal gears are cut than when external gears are cut. The influence of this force on the machining error is determined by the gear pitch parameter. It is shown that the most rational way to reduce the machining error is to reduce the cutting force by reducing the axial feed rather than by increasing the number of passes.Item Study of durability in the connection “cone-tungsten carbide insert” for tension dependence(Видавництво Львівської політехніки, 2023-02-28) Slipchuk, Andrii; Jakym, Roman; Bembenek, Michal; Lviv Polytechnic National University; Drohobych State Pedagogical University by name I. Franko; AGH University of Science and Technology in KrakówDuring and after the technological operation of pressing these factors significantly determine the residual stress states of tungsten carbide inserts, as well as in the areas near the holes of the cones’ crowns of the cone. The stressed state of the inserts and the magnitude of the stress concentration determine their fatigue strength of them and the durability of the inserted carbide rockblasting equipment of the cones in the area where the inserts the cone. Dimensional analysis was done for the inserts and holes in the cones of bit and it was established that size errors of component links of dimensional chains are distributed according to laws that are similar to the normal law of distribution of random variables. The test was carried out according to the criteria of Pearson and Kolmogorov. The influence of various random and systematic factors results to the dispersion of dimensions on the dimensional processing of conjugated surfaces. The amount of tension is a function of the dimensions for mating surfaces during assembly operations. Dispersion of dimensions for the component links of the dimensional chain of a press connection causes the formation of a practical field of dispersion of the closing link. Accuracy control for the closing link in the dimensional chain is impossible if there are no direct measurements of the constituent links. A mathematical model of the process of assembling “cone-tungsten carbide insert” joints was created. For this, the methods of mathematical statistics were applied in the study. It was established that the tension values have a greater influence on the force of pressing inserts into the holes of drill steels 14 NiCrMo1, when its hardness value is HRC 59–60 compared to HRC 48-50. This dependence has a linear character within the limits of the studied tension values. The established relationships make it possible to reasonably and most accurately form selective groups of inserts and mark holes for them. This method significantly reduces losses in the production of drilling tools.Item Improvement in the construction of the “Tungsten carbide insert cutter – cone” joint for tricone drill bits(Видавництво Львівської політехніки, 2022-02-22) Slipchuk, Andrii; Jakym, Roman; Novitskyi, Jurii; Lviv Polytechnic National University; Drohobych State Pedagogical University by name I. FrankoMeet a claim is quite difficult in real production, even in specialized drilling manufacturers. Therefore, the development of reliable criteria for approaches to improving the technology of tricone drill bits is an urgent problem. This is great practical importance for domestic enterprise. The task is set to create rock-destroying insert in the basis of the developed construction. This allows you to increase the reliability of the connection between the cutter insert and the body of the cone. Favourable conditions should be provided for the rational distribution of contact stresses in conjugate surfaces “carbide cutter insert – bush – body of cone”. Crucial part here is required rigidity of the carbide cutter insert. Advanced requirements are placed on them regardless of the design and dimension-type of tricone drill bits. They must have higher requirements such as: high reliability, durability of responsible elements of support and rock-destroying equipment, productivity, ability is stand destructive forces and torque are brought through a bit for influence on a face. This increases the reliability of its connection with the body of the drill bit. Requirements apply to the design to provide favorable conditions for the rational distribution of contact stresses in conjugate surfaces “carbide cutter – bush – body of the bit cone”. The obtained results of stress state modeling indicate that, as expected, with the same forces acting on the insert cutter from 42 kN to 57 kN, the most intense place on the cone will be the “collar” near the cutter. The intensity of stress will be up to 1050 MPa in this place for cones with serial rock-destroying equipment. At the same time, the intensity of stress will be up to 900 MPa for cones with developed destructive equipment, this is 14 % less.Item Mechanisms of structural-phase transformations during crystallization of a solder melt(Lviv Politechnic Publishing House, 2020) Kuzey, Anatoliy; Lebedev, Vladimir; Slipchuk, Andrii; Tsykunov, Pavel; Yurchyshyn, Igor; State scientific institution “Physical-Technical Institute of the national academy of sciences of Belarus”; Lviv Polytechnic National UniversityProblem statement. An important requirement is quality assurance of joining materials with minimal overheating of materials, lowering the soldering temperature and suppressing the interaction of the solder with the materials to be soldered. The heating of the solder and the holder should be as uniform as possible and with a minimum temperature difference along the depth. One solution may be to develop more efficient solders and fluxes, adapted to the high heating rates that are typical when using high frequency currents Purpose. Thus, the problems of uniform heating of parts during brazing are relevant. This is necessary for optimal distribution of the electromagnetic field in the contact area Methodology. The effect of the heating rate was investigated. The composition of the flux and solders on the microstructure of the solders and the brazed seam was performed on the joints of HV510 (DIN), HS345 (DIN), HG30 (DIN) hardmetal plates with steel holders made of 5135 (USA) steel with a section of 25×20. Results. The research of the processes showed that during the contact interaction of low-melting and refractory components of the solders, when the tool was soldered, the solder is formed in the seam and proceeds through several stages. Practical value. Contact interaction of copper-zinc melts with iron particles does not lead to complete dissolution of iron particles. This is explained to the low values of the solubility of iron in copper-zinc melts despite the fact that resistive heat release occurs in the particles. Such iron particles (iron-based alloy) act as a dispersed phase in the structure of the composite material.