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Background. The variety of polishing systems and tools available for finishing direct composite restorations may perplex the dentist.Objectives. An effect evaluation in one- and multi-step composite polishing tools using model specimens of GC Gradia Direct and 3M ESPE Filtek Ultimate restoratives.Methods. The prepared specimens of GC Gradia Direct and 3M ESPE Filtek Ultimate restorative composites were exposed in laboratory to the Kenda Maximus, Dentsply PoGo, Kagayaki RoundFlex, Shofu Super-Snap, Kagayaki Ensmart Pin, EVE Composoft polishing systems and Daiyamondo Kagayaki paste. The polishing systems distinguished by brand, technical and performance characters.Surface microgeometry in all 16 samples was estimated in the Laboratory of Optical Metrology, Institute of Design and Technology for Scientific Instrument Engineering, Novosibirsk, using a MNP-1 light interferometric nanoprofile microscope and at the shared core facilities of the Research and Education Centre “Nanomaterial Diagnostics and Properties” of Kuban State University, Krasnodar, using a JEOL JSM-7500F scanning electron microscope.Results. Optical profilometry and scanning electron microscopy were used to estimate surface roughness in 16 specimens exposed to polishing for one minute. The polishing tools Kenda Maximus, Dentsply PoGo, Kagayaki RoundFlex, Shofu Super-Snap, Kagayaki Ensmart Pin, EVE Composoft, as well as Daiyamondo Kagayaki paste used in instrumental polishing, revealed a varied performance. Optical profilometry exhibited the GC Gradia Direct and Filtek Ultimate specimens to possess the lowest average roughness in two cases: 1) after multi-step polishing with Kagayaki Ensmart Pin tools with Daiyamondo Kagayaki paste (average roughness corresponded to Sa — 0.214 pm in GC Gradia Direct and Sa — 0.248 pm — in Filtek Ultimate), 2) in application of the Kenda Maximus monopolishing tool (roughness values of Sa — 0.211 and Sa — 0.242 pm, respectively). Surface roughness after multi-step machining with EVE Composoft silicone polishers was average Sa — 0.579 and Sa — 0.549 pm in both samples and was reported the highest. Scanning electron microscopy confirmed the optical profilometry estimates.Conclusion. The assay showed that the specimen machining with a sole Kenda Maximus diamond abrasive tool and several Kagayaki Ensmart Pin silicone polishing heads followed by a Daiyamondo Kagayaki diamond abrasive paste application produced very similar surface roughness values, which were graded the lowest with GC Gradia Direct and 3M ESPE Filtek Ultimate composite samples using scanning electron microscopy and optical profilometry.

Introduction. The study results of the abrasive processing of parts made of polymer-composite materials are presented. The features of processing polymer composites and the technology of preforming through waterjet cutting are described. The stages of preparation of a part made of polymer-composite material for the “glueing” operation are investigated. Materials and Methods. Dependences for determining the surface roughness under waterjet cutting of polymercomposite material are considered. Research is carried out to achieve the required surface roughness under adhesive bonding of workpieces. The dependence is given that describes the roughness that is required for a reliable adhesive bond. Results. The theoretical and experimental studies of the waterjet cutting process are resulted. Their implementation technique, the tool and equipment used are described. The results of theoretical and experimental studies are compared. Their high convergence is established. The results of experimental studies on the preparation of parts made of polymercomposite materials for glueing are shown. The abrasive tools and processing modes are selected. Discussions and Conclusions. The process design procedure of abrasive treatment of workpieces from polymercomposite materials is proposed.

Introduction . It should be noted that the study on the problem of the effect of the mass of parts on the vibration-abrasive processing is insufficient. In the works of A.P. Babichev and M.A. Tamarkin, the fact of such an effect is mentioned, but the degree and mechanism of the effect are not disclosed. In the metal removal formulas, only the number of interactions leading to microcutting is taken into account. The present work objective is to determine the effect of the mass of parts on the metal removal rate under vibroabrasive machining. Materials and Methods . An empirical, i.e., experimental, approach is used. Parts from D16 and 30KhGSA materials which are widely used in the aviation industry were selected as samples. To change the mass, holes were drilled in the blanks; lead was poured into some samples, and plugs made of the same material as the blanks themselves were clogged into the others. Thus, experiments were carried out with solid, hollow, and weighted with lead samples. The working abrasive medium was scrap of grinding wheels of 40 x 80 mm, 25 grain size, and of trihedron prisms of 15 x 15 mm, 16 grain size. The experiments made it possible to clearly demonstrate the effect of grain size on the removal rate of the workpiece. Results . The parameters of the effect of the mass of parts on the removal rate under vibroabrasive processing are determined. The results obtained show the removal per unit area. The data are approximated by the least squares method with a linear function. A version of its distribution is selected using the Fisher statistical criterion. Discussion and Conclusion . It is shown how the workpiece mass determines the specific removal rate under the vibroabrasive machining. In the future, the database which is used to determine the effect of the work material characteristics on the process under consideration should be replenished. This will allow introducing a correction factor for the influence of mass in the metal removal formula, which will provide more accurate prediction of metal removal at the design stage of technological processes of vibration-abrasive machining.

IIn the Urals, there are more than a hundred products with large-diameter holes, some of which are made using a copper tube. Experiments on hollow drilling in the expedition of S. A. Semenov have shown great complexity of this method. In experiments on drilling it was planned to identify labor costs for the manufacture of copper tube, and also reveal various aspects of drilling techniques. The article presents the results of experiments on drilling different types of stone (soapstone, marble, serpentine and jade) with a copper tube. Experiments have shown that drilling with a brace is 1.5 times more effective than drilling with a borer. And using a copper tube as a drill increased the speed of making holes by 4-7 times. It also turned out that the abrasive used is very important for drilling efficiency. The most effective abrasive was emery, whose deposits are known in the southern Urals. The results obtained allow the authors to establish with great accuracy what drills and with application of what equipment stone axes of Bronze Age were drilled. A comparison of the experimental drills with bronze age drills shows that drilling with a copper tube was often, but not always, performed using a special machine tool. Labor-intensive making stone axes with large diameter holes especially made of strong row materials attest about high social status of their owners. © 2021 Academy of Sciences of Tatarstan, A.Kh. Khalikov Archaeology Institute. All rights reserved.

Introduction. The development of the final abrasive processing of parts from polymeric composite materials with the use of the flexible grinding tool is considered. The research objective is to reduce the processing time through displacement of human labour by mechanized work, as well as to improve the treated surface quality. Materials and Methods. The method of surface preparation of parts made of polymeric composite materials (PCM) is used for gluing through the mechanical abrasive treatment with a flexible grinding tool. Research Results. Characteristic features of forming the surface microprofile of GRP parts after treatment with a flexible abrasive tool by hand and mechanical methods are analyzed. Need for mechanization of the given operation is determined and validated. The surface parameters affecting the formation of a quality adhesive bond are described. The design features of a flexible grinding tool and their effect on the formation of surface roughness are considered. Data of the surface microprofile treated by a grit cloth and a flap wheel under various cutting conditions are compared. Discussion and Conclusions. Mechanical processing by flap wheels can replace manual sanding of parts made of polymeric composite materials, drastically reduce the operation time, and improve quality rating of the part surfaces for pasting

Introduction.The article discusses the question of applicability of the calculation assessment method of resistance for details from gray cast iron after thermal diffusion hardening. The purpose of research is to check applicability of the calculated model for determination of intensity in case of the variable blanket hardness.Materials and methods.The model of intensity dependence on contact of two disks of friction gear is used in the research. Calculated determination of parameters is executed in two options: contact of the steel disk and disk from gray cast iron with the strengthened layer, and contact of the steel disk and disk from the tempered high-strength cast iron. Thus, roughness corresponding to the earned extra surface in contact zone is created. Experimental check of received results is carried out by means of specific work of abrasive wear definition for gray cast iron with the strengthened layer and the high-strength tempered cast iron.Results.As a result, it was established that the resistance of details from gray cast iron with the strengthened layer is comparable to high-strength cast iron after hardening. The results of experimental check prove the obtained calculations since the parameters values of resistance received would be well coordinated. Therefore, the possibility of the calculated resistant technique usage for such case could be considered as proved one and, therefore, it could be used at design calculations of the frictional units containing details from gray cast iron with the strengthened layer.Discussion and conclusions.The considered way of superficial hardening needs to be applied depending on features of operation on frictional unit. In such case, when the allowed values of wear change in wide limits (for example, brakes, coupling, etc.) it would be better not to subject a blanket to machining where the formation of optimum parameters of friction surfaces happened in natural way, or it would be necessary to delete an allowance. This suggests that the calculation method of the determination of layer resistance enables to define concrete values of an allowance which needs to be deleted.

A mathematical modeling of geometric and kinematic relations has been made in respect of an operational zone for one of the standard machine tool sections which is used for simultaneous double-sided abrasive processing of highly-accurate lenses with a small rigidity (with a thin centre) under free lapping conditions. An analytical expression has been obtained for calculation of a sliding velocity in an arbitrarily selected point either on a surface to be processed or on a processing surface. As the proposed technology for simultaneous double-sided processing presupposes oscillatory motion of only processing tools then in order to eliminate a joint opening (a local contact fault between lapping surfaces of a tool and a work-piece) length of a drive piece must be not less than a specified value. In this case a convex tool is rigidly connected with a drive piece and it makes a reversing rotary motion (an oscillatory motion) around a centre of the processed spherical surface and a hinged joint of the centre with an output element of the technological equipment actuation mechanism is realized by transition of the drive piece ball end with a spherical seat in the output unit. In order to reveal analytical dependence of tool drive piece length on radius value of the processed spherical lens surface and friction coefficient in the contact zone of the tool and a work-piece the paper has considered a flow pattern of force while processing concave surfaces of lenses having small radius of curvature in case when the tool is positioned at the top. The friction coefficient included in the obtained expression has been determined for grinding while using suspensions of М40, М28, М10 micro-powders in a cast-iron grinding instrument and polishing while using polyrhythm suspension in a pitch and urethane-foam polisher. A method of the inclined plane has been used in this case and following the method a work-piece of optical glass has been initially lapped to the tool with the help of the appropriate abrasive suspension and the required angle has been determined at the moment when the work-piece started its sliding movement along the tool surface.

Introduction The problem of tight joint of pipelines and high pressure hoses (HPH) applied in various fields of human livelihood is considered. Special aspects of the high-pressure pipelines operation in the equipment of the oil and gas complex is as follows. At ambient temperatures below minus 50oC, it is needed to transmit thousands of tons of stratum fluids heated up to 200-250oC and containing aggressive media, abrasive and highly mineralized water. Materials and Methods. Various designs of metal seals applied in high pressure pipe connections are considered. Joints widely used for pipelines do not withstand pressures higher than 20-60 MPa. With that, in pipelines of the oil-industry equipment, pressure may exceed 100 MPa. A key feature of applying joints in question is to reduce their strength with increasing the diameter. These detriments confine the scope of use of the above-mentioned sealing schemes. It makes field repair of such joints, for example, during operation of oil and gas equipment, practically impossible. In this case, the use of quick connectors (Q/C) is required, for disassembling of which it is ample to have the keys. Research Results. For the solution to the specified problems, a principally new scheme of connection sealing for pipelines and HPH is developed and patented. The key element of the patented device is a stepped bushing which reliably seals the connection of pipelines and HPH. The stepped bushing (sealant) should be made of high-alloy steel by analogy with the joint in the flange couplings, and it can be hardened which will allow for increasing the strength of the connections in question and using them under low temperature conditions. Discussion and Conclusions. The comparative analysis of the sealing elements designs shows advantages of the proposed sealant. For its practical application, it is needed to optimize the shape and dimensions of the stepped bush in order to provide for leaktightness at given pressures, and, besides, to determine the required thread pull force to ensure safe performance of the unit.

In this work receiving composite materials on the basis of refractory connection – transitional alloy from a nikelid of the titan is considered. TiNi alloy has the high level of damping. Use of this binding material allows to increase significantly heat resistance, durability, plasticity and by that abrasive wear resistance the dezintegratornykh of installations in use beat. For conditions of road construction by the most suitable superthin crushing of mix as the most productive and less power- intensive process is. The izmelchitelnykh of installations is the advantage of this type their comparative compactness.

The analysis of possible variants of reconstruction of the power equipment is fulfilled and the conclusion concerning the prospects of such work with the use of composite materials is reached. The data on the technical characteristics of composite repair materials for various purposes are presented, the results of repairs of power equipment, in particular the technology for the recovery of the boarding surfaces of the diffuser rings and protection of the pumps D1250 casings are provided. The technology of the recovery pneumatic cylinder, hydraulic cylinder rod, as well as the unique technology of restoration of working surfaces of the impeller vanes of transfer pump, that had been destroyed by corrosion in conjunction with the cavitation processes and were considered as not restorable is described. The restored impeller was in operation during a year and only thereafter it was removed for restoration. Another composite material discussed in the article – diagum – makes it possible to perform a series of repairs associated with restoration of the rubber-covered surfaces of pump casings as well as with restoration of various surfaces of the conveyor belts. Taking the excellent adhesive properties of this composite into account, restoration of worn stainless steel sieve screens to remove abrasive material was fulfilled with the aid of it. The restoration was accomplished via the use of the conveyor belt which application time had expired, that was glued to a metal sieve with diagum. The use of the composites is economically justified, because the application of them in repairs reduces, firstly, terms of restoration work and, secondly, the price of repairs. Third, equipment that was damaged beyond repair is being commissioned by the use of the mentioned composites.

Описан метод испытания стальных материалов на изнашивание о нежестко закрепленные абразивные частицы в планетарном грануляторе. Изучено влияние фракционного состава катализаторов установки каталитического крекинга на абразивный износ системы гравитационного тракта установок каталитического крекинга. Исследования проведены в соответствии с методикой планирования экспериментов. Установлено, что определяющую роль в износе стальных образцов играют фракции более 3,15 мм. Методика эксперимента может быть использована для испытания других материалов., A method of testing steel materials for wear on loosely fixed abrasive particles in a planetary granulator is described. The effect of the fractional composition of catalysts for a catalytic cracking unit on the abrasive wear of the gravity path system of catalytic cracking units is studied. Studies conducted in accordance with the methodology of planning experiments. It has been established that fractions >3.15 mm play a decisive role in the wear of steel samples. The experimental method can be used to test other materials.

Рассмотрен процесс обработки плоскостей торцевыми полимерно-абразивными щетками различной зернистости. Исследования проводились экспериментальным методом на торцевых щетках Scotch-Brite™ BD-ZВ различной зернистости компании 3М. Установлены закономерности влияния частоты вращения, деформации ворсин щетки и подачи на относительный съем материала и шероховатость обработанной поверхности. Полученные результаты представлены в виде математических зависимостей. Применение торцевых полимерно-абразивных щеток для финишной обработки плоскостей является целесообразным. В зависимости от требований по параметрам шероховатости на изделие можно эффективно управлять процессом путем изменения режимов резания и зернистости материала щеток., The article deals with the issue of improving the efficiency of the grinding process of blanks of technical ceramics. For the design of machining operations it is required to assign rational parameters of diamond wheels according to the physical and mechanical characteristics of the processed materials—hardness, strength, brittleness. On the basis of statistical studies, a mathematical model of the distribution of grain heights in the diamond-containing space in the grinding of composite materials is obtained. This model allows you to control the machining process due to the law of distribution of grain heights in a bunch of circle.

The problems of intensity of wear of details of the cars working in the oil polluted by abrasive particles, depending on mechanical properties of material of details and abrasive particles, their sizes, a form and concentration, loading, temperature of a surface of friction, speed of sliding, quality of lubricant are considered.

Актуальными остаются вопросы в области повышения качества обработанных шлифованием поверхностей изделий из древесины и материалов на ее основе, а также вопросы, связанные с повышением стойкости шлифовального инструмента. Рассмотрены и обоснованы методы повышения стойкости абразивных шлифовальных лент при обработке древесины и древесных материалов. Работоспособность и стойкость шлифовального инструмента во многом зависят от физико-механических свойств материала режущего инструмента и материала обрабатываемой заготовки, режима резания и его назначения, геометрии абразивного зерна, способов его нанесения на шлифовальную ленту и условий обработки. Возможными вариантами повышения стойкости шлифовальных лент являются: использование различных конфигураций рифленых и более твердых контактных валов и применение режущего инструмента на основе самозатачивающегося абразивного материала, способного в процессе обработки обнажать новые острые режущие кромки. Первый вариант позволяет повысить стойкость шлифовальных лент, но при этом в зоне резания создаются наиболее благоприятные условия для возникновения повышенных температур, ведущих к повышенному теплообразованию в зоне резания и образованию на обработанных поверхностях прижогов, также данный способ трудоемок в плане переналадки шлифовального оборудования. Второй способ более актуален и прогрессивен, позволяет при увеличении удельного давления прижима контактного вала к обрабатываемой поверхности заготовок обнажить новые режущие кромки абразива, а также улучшить качество обработанной шлифованием поверхности, но при этом остается открытым вопрос экономической целесообразности применения данных абразивных материалов на ряде отечественных производств., Urgent questions remain in improving the quality of the treated by grinding surfaces of wood products and materials based on it, as well as issues related to the increasing resistance of the grinding tool. Methods of increase in resistance of abrasive sanding belts when processing wood and wood materials are considered and proved. The working capacity and resistance of the grinding tool in many respects depend from physics-mechanical properties of material of the cutting tool and material of the processed preparation, the mode of cutting and its assignment, geometry of abrasive grain, ways of its drawing on a sanding belt and processing conditions. Possible options of increase in resistance of sanding belts are use of different configurations of corrugated and firmer contact shaft and use of the cutting tool on the basis of the self-sharpening abrasive material capable in processing to bare the new sharp cutting edges. The first way allows to increase resistance of sanding belts, but at the same time in a zone of cutting optimum conditions for emergence of the increased temperatures leading to the increased heat generation in a zone of cutting and to education on worked surfaces of burns are created and also this way is labor-consuming in respect of readjustment of the grinding equipment. The second way is more relevant and progressive, allows at increase in specific pressure of a clip of a contact shaft to the processed surface of preparations, to bare the new cutting abrasive edges and also to improve quality of the surface processed by grinding, but at the same time there is open a question of economic feasibility of use of these abrasive materials on a number of domestic productions., №222 (2018)