The article deals with a new system of a vibration-damping tool, the effect of which is achieved by a combination of the multi-layer principle and the use of anisotropic properties of sheet metal. Operation of such tool systems in turning operations can reduce high-frequency vibra-tions arising in the process of cutting due to the ordered disorientation of anisotropic plate texture of a multilayer modular tool holder that allows you to efficiently dissipate oscillatory wave energy at the boundary of transition between the plates of the tool holder. This method allows increasing the resistance of the tool cutting edge significantly and expanding the technological capabilities for the effective selection of cutting modes to ensure compliance with requirements for dimensional and geometric accuracy, quality of processed surfaces of powered roof supports, hydraulic units, mining machinery and equipment.
The paper considers the application of polymer composite materials in friction units of downhole oil pumps. The proposed scheme test samples of various composite materials paired with a steel roller adopted by the size of the spots wear using the criterion of resistance. As it is shown significant influence on the wear resistance of the friction pair, working in the crude oil environment, has not only the composition but also the reinforcing fibers direction. The best re-sults were obtained for a sample of polyamide reinforced with 50 % of high molecular weight synthetic fibers placed perpendicular to the friction surface.
Offering modern methods of processing and briquetting metal chips in automated production. Considered the basic types of equipment, a scheme for constructing the production line processing chips, identified key issues related to the management process of chip formation, chip crushing, cleaning chips from cutting fluid and briquetting.
The article describes the static and dynamic characteristics necessary for the assessment of the properties of the technological system. It is shown, that the basic static and dynamic characteristics are the stiffness of the bearing systems of the machine, the geometric precision and accuracy of the sizes and the form of the processed product. In the paper a method of constructing dynamic models of small dimensionality, on the basis of which the modeling and management of technological systems of mechanical processing. The dynamic characteristics of the techno-logical system of defined areas of sustainability of the process of cutting.
The paper describes an effective method, which permits to control the machining of hard-to-handle materials under local pre-strain and facilitates generation of structural metastability on the outer layer of the process material. Authors propose a new approach to creating local metastability in the machined material using thermal, plastic and cryogenic treatment. Changes in material properties, occurring under local deformation, are presented in a widely used graphic form of a stress-strain curve. In experimental tests, performed under local plastic strain, the authors observed normal vibration displacement of the tool in relation to the surface of the workpiece, made of medium-carbon steel (0.45 % C). Theoretical and experimental results confirmed the possibility to control the cutting process and to deliver dynamic stability for high-precision machining. The study allows to improve existing technologies for a wide range of materials and cutting modes, to implement segmentation and breaking of the chip in the shear zone, and to apply controlled robotic systems on CNC machines.
The occurrence of fretting corrosion on nominally fixed surfaces of high-loaded parts of mining machines and mechanisms is considered. Examples of wear and damage of critical parts, bearing assemblies of engines of dump trucks in fretting conditions are given. The mechanisms of fretting corrosion when using wear-resistant coatings are considered. It is noted that when choosing protective thin-layer coatings that provide an increase in the fretting-resistance of surfaces of tightly contacting parts, it is necessary to take into account both their wear resistance and the ability to resist shear. At the same time, the thickness of such coatings allows preserving, during operation, those provided during the assembly of the tension, without disturbing the maintainability of the nodes. The results of research of fretting wear of a number of coatings on a special installation are given. The mechanisms of wear of a number of thin-layer coatings based on friction-mechanical brazing, polymer fluorocarbon composition, solid lubricant coating using scanning electron microscopy were studied. Recommendations on the use of the studied thin-layer coatings for high-loaded parts of mining machines operating in fretting corrosion conditions have been developed. The aim of the work was to study the effect of a number of thin-layer coatings on the wear of highly loaded connections of the mechanisms of mining machines, in particular bearing assemblies of quarry dump trucks operating under fretting corrosion conditions.