The paper considers a technological process for production of sealing rings by winding a band work-piece on a cylindrical caliber mandrel with subsequent endurance under load and further cutting of a spiral in rings and also studies the possibility to obtain products while using a method for cold forming of a work-piece which excludes thermal stabilization operation. Taking into account the fact that fluorine plastic is a high-plastic material even at very low temperatures such technology looks quite real. Therefore winding of a band on a mandrel, endurance of a spiral work-piece without heating but under conditions of force action within the time which is necessary for completion of relaxation processes, and the subsequent cutting in rings will allow to obtain finished ring products of the required size. However fluoroplastic has specific mechanical properties and a number of specific features which are revealed during deformation process. Its deformation behavior considerably differs from behavior of low-molecular materials and therefore it requires a solid approach while using the existing theoretical base and developing calculation methodologies. While taking into consideration the fact that fluorine plastic is high density material and has structure with high degree of crystallinity, the mechanism of deformation behavior in it under conditions of a force field is mainly similar to metal behavior that allows to use methods and approaches for calculation of fluoroplastic products which are accepted in mechanics of solid bodies. However the applied calculating formulae require a certain correction and adaptation to specific features of mechanical fluoroplastic properties, one of which is its various rigidity at stretching and compression that is revealed in case of winding band work-piece on a mandrel. Fluorine plastic is a material with various modularity and its rigidity is higher during compression than under stretching and consequently in the case of band bending a neutral axis of section is displaced from the center of gravity to the area of compressed fibers, and the area of stretching is increasing. High elasticity at stretching and increase of this area lead to large accumulation of elastic deformations causing springing after unloading and changes in size of a finished product. These facts must be taken into account while calculating and designing a mandrel tool, it is also necessary to keep in mind various modularity of a material and possibility that a section being led to an uniform rigidity may take some other shape due to this. Calculation methodologies have been developed by the authors for both versions of section that take into consideration directly or indirectly a material with various modularity and which do not contradict each other and which are rather precisely proved by experimental data.

In mechanical engineering, various types of bearing units are used in moving connections and sliding pairs (sliding bearings, guides, bushings) are sufficiently widely used. This allows increasing the stiffness of the units, reducing their dimensions, improving heat dissipation, etc. But there are higher friction losses, probability in the increases of situations in which there is a jamming of friction surfaces for application of sliding friction pairs compared to the rolling bearings. These problems are even more important for application of sliding bearings in precision equipment, which typically operates under temperature and humidity stabilized conditions. The aim of the work is the development of methodological approaches to the creation and rational design and manufacture of sliding friction pairs based on the composite antifriction materials’ coatings for the application in vertical precision program-controlled electrospindles for high-speed machining. Questions of development and manufacturing of friction units for precision electrospindles with high rigidity on the basis of composite materials are considered. It is shown that acceptable cutting speed (750 m/min or more) for the quality standpoint of processing with a diamond-like tool can be achieved by placing the cutting edge of the tool on diameter of 200 mm. As a result, two tasks solved: the rigidity of the electrospindle for ultra-high accuracy of mechanical blade processing is achieved; high smoothness of work is provided, which allows achieving nanometric surface roughness with a decrease of deviations to 1 µm from the middle surface line. It is extremely important for a number of special applications.

However, the ECP in its classical form has a number of significant drawbacks. One of them is a dependence of treatment modes and electrolyte compositions on the processed material. In addition, aggressive expensive electrolytes that require special technologies for disposal are used for ECP. Electrolytes in ECP often require heating to a temperature of 60–90 °C. Processing at such temperatures causes significant harm to the environment and production personnel. To eliminate the existing disadvantages of the ECP and expand its technological capabilities, a processing method with application of pulsed unipolar and bipolar modes has been proposed. As a result, fundamentally new processes of pulse ECP with a pulse duration of 0.05–20.00 ms have been developed. They provide a reduction of energy costs for the process and high efficiency of polishing in comparison with traditional DC polishing. The rate of smoothing micro-roughness of the treated surface related to the total metal removal is significantly increased. The use of pulse modes in comparison with traditional ECP allows processing in universal electrolytes of simple compositions based on sulfuric and orthophosphoric acids without addition of chromium anhydride. Application of the developed pulse modes, which will provide at low metal removal a significant change in surface roughness, is the most appropriate for the ECP of precise parts, products or parts of small cross-section and rigidity, such as medical devices for minimally invasive surgery, precision engineering parts, etc. The paper presents results of a study for influence of pulsed unipolar and bipolar ECP modes on the surface quality of stainless steel specimens, as well as a comparative analysis of the efficiency of using pulsed ECP modes instead of DC polishing. The technological parameters of ECP using pulsed modes, providing the highest quality surface polishing with high efficiency of micro-roughness smoothing and low energy consumption have been established in the paper.

An electric screwdriver was designed to work in an automatic cycle on assembly lines. A characteristic feature of the screwdriver is the use of a low power motor in comparison with commonly used devices. The work of tightening the threaded joint takes place at the expense of the kinetic energy of the components of the drive system and the working screwdriver. It has been proved that the ability of the screwdriver to perform the tightening work is determined by the sum of the mass moment of inertia of the working components system and the mass moment of inertia of the motor's rotor, reduced to the axis of the screwdriver bit. The process of tightening is characterized by the number of screwing pulses, screwing torque values at the end of each pulse and the time of screwing process. The limitation of the value of the transmitted tightening torque takes place through the applied overload coupling.  The construction work of the screwdriver was preceded by the development of a mathematical model of the process of screwing and balance of torques acting during each phase of operation was carried out. This allowed the calculation of the value of the kinetic energy of components of the drive and operating system translated into the tightening work. The kinematic conditions to be met by the screwdriver at the end of a single tightening pulse were determined in order to accumulate kinetic energy and start another tightening pulse.

The modern industrial production of the Republic of Belarus is characterized by the absence of its own raw material base and significant dependence on imported energy carriers and material resources supplied at world prices. When working in such conditions, production efficiency can be achieved through all-round economy and creation of modern energyand resource-saving technologies. However implementation of such technologies, for example, laser cutting and welding, cladding, flame spraying, painting, etc. directly depends on quality of cleaning metal surfaces from corrosion. Theoretical and experimental studies conducted at the Department of Shipbuilding and Hydraulics of the Belarusian National Technical University have shown that it is very economical to remove corrosion products from metal surfaces using new technology of reverse jet cleaning. The reverse jet cleaning technology is based on a physical principle which presupposes that a jet of working fluid (pulp based on river sand or bentonite clay) rotates 180º when it hits the surface to be cleaned and it leads to an increase in jet impact on the surface to be cleaned by 1.5–2 times due to occurrence of a reactive component. In order to ensure a marked jet reversal an original case design has been developed which is characterized by a patent novelty. One of the main elements in this design is a confuser-shaped stream-forming device. Theoretical investigations on pressure losses of working fluid in a confuser channel which are based on the study of functional at the extremum have made it possible to obtain a dependence for calculation of an optimal cone angle at a turbulent mode of motion within the range of Reynolds numbers 4000 < Re < 3 ×10⁶ while taking into account an influence of working fluid density, its dynamic or kinematic viscosity, average velocity movement of working fluid, confuser radii.

Results of the analysis of scientific, technical and patent literature show that while having a great variety of constructive implementation of the proposed catchers there are no efficient and sufficiently reliable devices for catching conveyor belts at its reverse motion which are relatively simple in design. This is proved by practical activity of enterprises involved in extraction and processing of commercial minerals and other industries. A new design of a conveyor belt catcher that meets most requirements for the given equipment has been developed at the Institute of Mining, Ural of Branch of the Russian Academy of Sciences and then it has been tested under industrial conditions. The design makes provision for retention of the conveyor belt at its reverse motion beyond free edges from transported material. Catching devices are installed on both sides of the belt. Braking action of the belt at the reverse motion occurs due to its friction interaction with a catcher friction shoe located above the belt, and an eccentric mounted on the frame under the belt. A friction shoe is made with a concave curved surface facing the belt. The paper presents a calculation methodology of main parameters for the proposed design of catcher conveyor belts that permits to determine a force catching a conveyor belt down and for every braking period distance which has been passed by the belt, value of its compression, value of braking force, braking time and acceleration of belt motion, time and length of the distance passed by the belt to its full stop, parameters of a catcher and supporting structures, and other parameters. The paper also provides results of calculations for main design parameters of catching devices with an inclined conveyor having a belt width of 1400 mm for two catcher design versions: with location of an eccentric under the belt, and a brake shoe over the belt (option I) and with location of the eccentric over the conveyor belt, and the brake friction shoe under the belt (option II).

Nowadays the field of application of products made from polymer materials is constantly increasing. These products find their wide application in the most high-tech industries such as automotive, aerospace and medical industry. Modern trends in the development of the automotive industry predicts that 75 % of the total car mass will be replaced with polymer materials by 2020 and other industries demonstrate similar trends. Regarding to this information, engineering companies that design parts of the automotive industry should have polymer material characteristics over an entire range of deformations up to destruction for their performance prediction. However, strength characteristics of products from polymers are different and depend not only on a polymer grade but also on technology used for part production. Existing literature review on this problematic area is rather rare. The purpose of this paper is to determine and analyze mechanical characteristics of widely used PPH030GP polymer obtained by extrusion and ABS, PLA polymers applied while manufacturing samples using an additive method (3D-printing) depending on the rate of high-elastic deformation. All the samples have been made according to the requirements of GOST 11262–80 and subjected to uniaxial stretching on a tensile machine UIT STM 050/300 at different speeds of clamp expansion. According to experimental results, stretching diagrams in conditional coordinates s–e have been obtained up to the point of failure for different rates of clamp expansion. It has been shown that while using the additive method, a direction of layers and adhesion between them, which depends on 3D-print parameters, have a significant effect on the part strength. Printing settings are indicated in accordance with the selected mode and a 3D-printer model. As a result of data processing, strength characteristics of PPH030GP polymer and ABS and PLA polymers have been determined to a sufficient extent, depending on the direction of printing layers and rate of high-elastic deformation. These data can be used to calculate strength of products by numerical methods and a finite element method in various software products.

The paper proposes a variant of discrete and continual strengthening of contacting elements of machine-building structures. One of the parts is strengthened discretely, and its counterpart is strengthened continually. The resulting pair combines positive qualities of two different types of strengthening methods. Investigations on stressed-deformed state of the treated fragments provides a basis for conclusion about high efficiency of the proposed combined strengthening method. While applying the method mechanisms of negative feedback between the stages “loading – contact interaction – friction – wear” are involved unlike with conventional versions of strengthening technologies. In this way, positive integral effect results from an application of the developed strengthening technology. This effect is significantly higher than the sum of effects obtained owing to application of every strengthening technology. In this case a favorable distribution of contact pressures between contacting bodies has been ensured. This, in its turn, leads to a decrease in wear that prevents a sharp increase in loads acting between bodies. Thus stabilization of the investigated processes occur. The papers considers stress-strain state of a representative fragment of the investigated system in order to demonstrate positive effects arising from the contact of strengthened bodies. Results of the calculations indicate validity of forecast assumptions. Indeed, the strengthened zones can bear high loads. However, due to high tribo-mechanical properties of the material in the hardened zones, friction and wear in them are much lower than for a base material. Due to this, all positive components of the total effect are formed. This effect is supported by the fact that a counterpart is processed continually. In particular, metals from aluminum-type materials are coated with a thin layer of oxides by forming them in a strong electric field of a special medium. Formed solid phases of oxides serve as a structural basis for formation of surface layers. In combination with discretely strengthened surfaces of counterparts the formed pair acquires high strength, antifriction and anti-wear properties.

Many countries exploit a large number of armored vehicles, developed and manufactured dozens of years ago. Due to this there is a necessity of its continuous modernization. An object of the research is an internal combustion engine for a ground armored vehicle with a 12ЧН15/18 diesel engine. Calculation of engine thermal balance components is based on an engine external speed characteristic. An analysis of thermal balance for a 12ЧН15/18-type diesel engine of a ground armored vehicles has been made with separation according to: heat being withdrawn from cooling system liquid to environment; oil of lubrication system in the internal combustion engine; efficiently used heat; heat being withdrawn along with exhausted gases; residual portion of heat. The paper presents characteristics on changes in heat release during loading modes of the diesel engine operation and also shows an influence of the diesel loading on amount of heat withdrawn by cooling water and oil of diesel lubrication system. Two versions of the cooling system are considered in the paper, namely: with regulation and without regulation. The paper contains description of evaluation pertaining to an influence of a regulating system on characteristics of the diesel cooling system, parameters of efficient power and specific and efficient consumption of fuel. The necessity has been proved to modernize a regular fan cooling system of the armored vehicle with the 12ЧН15/18-type diesel engine. An influence of an average cooling liquid and diesel oil temperature with loading modes of 60 and 80 % on the efficient power of a power unit with a fan-type cooling system has been investigated in the paper. It has been determined that an increase in average temperatures of cooling liquid and oil for the 12ЧН15/18-type diesel makes it possible to improve economy and power of the diesel engine.

The paper presents investigation methods which are aimed at increasing an accuracy in determination of parameters for movement of vehicles in the reconstruction process of road traffic accidents. The problems with a target to improve a method for calculation of vehicle movement speed and location coordinates at different time moments have been solved in the paper. In order to determine more accurately nature of vehicle damage and their location on carriageway, a laser scanning method has been applied which makes it possible to reduce an error while determining dimensions and distances, and to shorten time for an inspection of the road traffic accident place. The presence of a scanned image in three-dimensional form allows more accurately to simulate nature and angle concerning approach of vehicles prior to a collision. A methodological support for determination of vehicle movement parameters has been developed on the basis of the recorded data from driving video recorders (DVRs). It has been established that an error in measuring a speed of movement for vehicles will depend on quality of a video image, length of the investigated area and range of possible speeds. A relative error will be the higher, the smaller we have vehicle speed range and length of the investigated section. A mathematical model of vehicle speed change in a differential form has been compiled and solved in the paper. The model allows to calculate a speed of motion at different time moments with respect to recording from driving video recorders. In addition, the developed methodology permits more accurately to determine coordinates of vehicle location on a photoand video image. This is especially important while determining places of pedestrian-road accident or vehicle collision location of the collision or the place of collision with regard to the edge of carriageway. Unlike subjective research methods when initial data for carrying out auto-technical investigations are established by interviewing witnesses and the accused, the proposed methods make it possible to permit reconstruction of a road traffic accident exclusively by objective methods with the help of automated technical means.