Bulletin PNRPU. Mechanical engineering, materials science

Sphere is the locus of points equidistant from its center. Control spherical surfaces required for parts of spherical bearings for aviation industry, large parts of machinery with spherical surfaces. With the aim of improving the quality of products are improving, as processing equipment, and control methods of products. Manufacturing is gradually moving from the simplest means of measurement for coordinate measuring machines (CMMS), which allow to automatically identifying geometrical deviations from specified dimensions and form of the parts. They have sophisticated design and powerful mathematical, algorithmic and software. Therefore, an important task will be the development of techniques for automated control, independent of the number of measurement points and their arrangement on the surface. Also to the fore the problem of providing performance control. The purpose of work consists in finding the most optimal method of processing the results of coordinate measurements of spherical surfaces on a CMM. In the process, we analyzed the possible algorithms for solving and finding areas. The analysis showed that the most efficient and optimal method of processing the results of coordinate measurements of spherical surfaces is the so-called method of the sphere of minimum volume. By results of research the technique of the automated estimation of sphericity on the basis of the minimum measured volume of spherical surfaces.

The electron beam is almost inertialess source of thermal energy. The ability to fine-tune the power and focus of the beam allows extensive use of beam control system and the programming of welding, providing high-quality formation of the weld. Using a beam control system may create new technological solutions, such as dynamic splitting of the electron beam, allowing the beam to simultaneously affect several treated areas, or to combine the processes such as welding and heat treatment. The results of experimental studies is a volatile reducing the concentration of alloying elements in the weld seams obtained by electron-beam welding of aluminum alloy AMg6 with oscillation of the electron beam. Obtained regression equations of the concentration is a volatile alloy components AMg6 of the welding parameters. Based on the results of X-ray analysis of the alloy assess depletion of volatile components in the various zones of the weld. It is found that with increase of the electron beam current, decreases the concentration of magnesium in the weld, however, increasing the welding speed, the concentration of magnesium is increased by approximately 2-3 %. By comparing the concentration of magnesium in the seams made static and oscillating beam, a decrease in the concentration of magnesium by the oscillation of the electron beam on average by 4 %. Electron beam welding static beam observed depletion magnesium within 7 % of the original content in the alloy, and in case of oscillations of the electron beam is about 10 %, and the trajectory of movement of the electron beam (longitudinal and transverse) does not affect the rate of depletion of the alloy volatile component - magnesium.

Researching object - the expensive diamond tool deterioration used at ruling of continuous and discrete grinding wheels is defined. Researching results of absolute and relative deterioration of diamond grains during grinding wheels ruling on various cutting regimes are presented. The diamond tool deterioration during grinding wheels ruling with a continuous cutting surface is studied in detail. However, deterioration researching of diamond grains at discrete grinding wheels ruling was not given proper attention that did not allow to make well-founded solutions concerning editing regimes of a discrete cutting surface and the demanded expenses of the expensive ruling tool. First, it concerns the fundamental indicator - the of diamond tool relative deterioration during the processing of abrasive grinding wheels material. Now in the scientific and technical literature there is no data on relative deterioration of the ruling tool, its values only for an edge cutting tool executed from a firm alloy and a tool steel are presented. The diamond tool relative deterioration during the processing of grinding wheels abrasive material with continuous cutting surface was determined. The regression equation connecting value of relative deterioration of the diamond ruling tool with a cutting depth at grinding wheels editing with a continuous cutting surface was obtained. The received value of relative deterioration allows to develop a calculating method of the diamond ruling tool absolute deterioration at editing of grinding wheels with a discrete cutting surface which is necessary for technological operations designing of metals and alloys discrete grinding.

The steadily increasing demands on the quality of parts instrument and aircraft bearings are responsible for the search for new technologies finishing. Currently, aircraft bearings are used the balls 20 degree of precision in which the tolerance for the diameter is not greater than 1 micron, spherical - 0.5 mm, waviness - 0.05 mm, roughness - 0.02 mm. Traditional finishing balls between two rotating disks is ineffective in the first place from the perspective of productivity. Therefore, scientific and technically justified application of centerless superfinishing balls on the machines with traverse with smooth rolls. It was established experimentally in principle the possibility of such a technological system for finishing ball bearings. The main advantage of this scheme processing is the high productivity and the possibility of complete automation of the process. However, the need to create a uniform rotation of the ball preform in two planes under power contact. For this solved the key problem of geometric and strength analysis of the conditions of stability of the power circuiting contact and profiling roll forming system superfinishing machine. The scheme of the forces in the superfinishing balls and revealed the condition of their movement with the rotation in two planes. A mathematical model of formation and describes the methodology for calculating the profile of the rolls by a numerical method. These results allow the use of centerless superfinishing balls as a finishing operation, instead of finishing, thereby increasing processing performance tenfold.

This review summarizes the studies of russian and foreign scientists on the preparation and evaluation of properties of advanced materials based on oxygen-free ceramics - ternary compounds or the so-called MAX-phases. The most experience in obtaining and study of the ternary carbides and nitrides has been gained in Drexel University (USA) a group of researchers under the leadership of M. Barsoum. In this article we reviewed a general characteristic of the structure for ternary compounds with a layered structure. Layered ternary carbides and nitrides exhibit a unique combination of properties characteristic of both metals and ceramics. Such materials have low density, high thermal and electrical conductivity, strength, low modulus, excellent corrosion resistance in aggressive liquid media, resistance to high temperature oxidation and thermal shock, and easily machined, has high melting point and are stable enough at temperatures up to 1000 °C. Among the many MAX-phases synthesized to date, the greatest interest from the standpoint of the level of their properties represent such materials based on titanium as Ti2AlC, Ti2AlN, Ti3AlC2 and Ti3SiC2. Shown the most successful ways of obtaining these materials: synthesis, reaction sintering, hot pressing, spark-plasma sintering, self-propagating high-temperature synthesis. A comparative analysis of physical and mechanical properties and the relationship "structure-properties" for materials for Ti-Al-C, Ti-Al-N and Ti-Si-C systems is shown. Indicates that in most cases the structure due to the methods of obtaining ternary compounds, is a multiphase system. Typically, these materials are ternary matrix with carbide and/or nitride inclusions and intermetallic compounds with a different degree of stoichiometry.

A study of several machine-building enterprises showed a very low technical equipment of the methods and means of control of main parts of internal combustion engines - camshafts, crankshafts and related parts. Existing automation tools for dimensional inspection - coordinate measuring machine of traditional design in the form of a three-axis devices with the movements of the measuring head of the touch coordinates X, Y, Z are not adapted for control of rotation bodies. So important are studies aimed at improving the accuracy and productivity of control of these parts and IT weapons designer, technologist, manufacturer or controller of high-speed automated methods and means of objective control in accordance with the requirements of modern production. Advantage and feature of the automated system of intelligent monitoring of manufacturing camshafts. is that in addition to the basic stages of measurements and the possibility of making decisions about the quality of product processing, the system can promptly inform about the deviations in the phases of monitoring, accompanying this information with the recommendations. Subsystem of monitoring of precision manufacturing of camshafts consists of: data collection system, including the communication device with the object; the decision-making system database and knowledge base. OFSTED are devices for the consolidation of analog and digital parameters of the real technical object. The database is constantly replenished "information store" in this case, the reference design documentation on the manufacturing technology of the product and the values of monitored parameters and actual measurement. The knowledge base contains structured information experts, for use for a specific purpose. Knowledge base is designed to find ways of solving problems from a particular subject area, based on BLM records and on the user's description of the situation. The introduction of a system of intelligent monitoring allows to increase the effectiveness of control several times, to ensure the correction of the technological process at the stages of product manufacturing that will greatly reduce the possibility of marriage, thereby increasing the quality of the products.