Wheel Surface Research Articles

Systematic Monitoring and Evaluating the Wear of Alumina Wheel When Grinding the Workpiece of Cr12

The performance of the grinding wheel demonstrably affects the machining efficiency and the quality of the workpiece. Therefore, it is essential to evaluate the wear of the wheel and then operate the dressing or replacement in time. The wear procession of the wheel was monitored and evaluated systematically in this paper. A surface grinding experiment was performed by using an alumina wheel to grind the workpiece made of Cr12. The grinding force and the grinding temperature were monitored and measured while the wheel grinds the workpiece. The surface topography of the wheel was also being observed. The distribution of the gray value of pixels in the image of the wheel surface was analyzed by the method of the histogram. Processing of the binary image of the wheel was performed after determining the gray threshold of the gray value. Then, the blockading and the wearing area on the grinding wheel were calculated. Moreover, the relation of the projection area of a single abrasive derived from theory and derived by image recognition was studied. The results of the grinding experiment show that wheel performance degradation occurs when the material removal volume reaches 210 mm3/mm. At this time, the ratio of blockage area on the grinding wheel reaches 13.4%. The percentage of the wearing area is 9.5%. The method of image recognition combined with grinding temperature is workable to realize monitoring and evaluating the wear of wheels on site without unloading them.

Machine Learning-Based Wheel Monitoring for Sapphire Wafers

The thinning of sapphire wafers is a key process that affects the quality of optoelectronic devices. In the grinding process for sapphire, a hard and brittle material, the grade and surface conditions (wearing and chip loading) of the grinding wheel are the key to continuous processing and reduction of defects. In industry, a common approach is to assume the possible causes of defects by observing the spindle current during the grinding process and the finished product after processing. Thus far, there has been no effective method to quantify the grade and no real-time monitoring technology for grinding wheels. This research proposes a wheel monitoring system that utilizes acoustic emission (AE) signals and radial/axial vibration signals to extract characteristic parameters via popular machine learning classification algorithms (k-NN, ANN, and SVM) in order to identify the signal and characteristic parameters of the wheel during the grinding process. The experimental results show that the AE signal identification accuracy of the grade is excellent, at 99%. The vibration signal of the wheel surface condition during the grinding process is significant as well, yielding an identification accuracy of 91%. The extracted signal characteristics in this research not only quantify the state of the grinding wheel, but also facilitate a wheel monitoring system based on the identification technology. The proposed method for grinding wheel processing status monitoring can be used to establish an automated intelligent grinding system.

Estimation of cBN grinding wheel condition using image sensor

The tool condition used in machining process is generally determined by the wear status, which is an important factor of resulting in the machining efficiency of the manufacturing processes. This paper presents a method to estimate the tool condition of grinding wheel using an image sensor with machine learning techniques. Statistical features, mean, standard deviation, and entropy were selected from the simplified wear model. The selected features were extracted from the wheel surface images of an electroplated cubic Boron Nitride (cBN) wheel on a commercial CNC machine, and compared to the tool condition represented by the number of grinding passes. Finally, the statistical features were fused by machine learning techniques to estimate the wear condition of the grinding wheel. Results show a sufficient correspondence between the estimated and true tool condition with 0.9590 of the coefficient of determination (R2) based on support vector regression model.

Effect of fine bubbles on grinding wheel surface during ELID grinding

Effect of fine bubbles on grinding wheel surface during ELID grinding

Characterization of Ceramics Grinding Wheel Surface Topography in Creep Feed Grinding

Characterization of Ceramics Grinding Wheel Surface Topography in Creep Feed Grinding

INCREASE OF EFFICIENCY OF DIAMOND GRINDING SUPERHARD OF MATERIALS

The analysis of algorithm of expert system of process of diamond grinding superhard of materials (SHPM) is given. For realization of the offered expert system the ways of grinding with the combined control of parameters of a working surface of diamond circles are developed.The designed ways of superhard polycrystallic material diamond grinding basing on control of a grinding wheel surface with usage of simulation of destruction processes of the system "polycrysta-grain–wheel bond" considered.

ТЕХНОЛОГИИ НАПЛАВКИ ВАГОННОГО КОЛЕСА

The article is devoted to the analysis of the quality of the metal deposited on the entire worn surface of the wagon wheel. The values of the specific energy of the multi-electrode surfacing process, determined by voltage and current, providing the necessary heat supply to the base metal to heat it up to 200 °C, have been experimentally identified. The technological sequence of surfacing wide-layer beads on the rolling surface and the wheel flange is presented. The adopted scheme of bead overlayingcreates favorable conditions for the course of thermal deformation cycles of surfacing. The quality of the bead formation is affected by the location of the electrodes relative to the surfacing surface. Depending on the required thickness and width of the bead applied to the cylindrical surface of the wheel, the diameter and number of electrodes, as well as the value of their displacement from the zenith, were selected. The reasons for the formation of defects and methods of their elimination are revealed. It has been determined that on optimal regimes without pre-heating the wagon wheel, it is possible to obtain metal without defects and brittle structures on the restored surface.

Experimental Analysis of a Grinding Wheel by Increasing Multiple Passes in Dressing

When sharpness of grinding wheel becomes dull, a dressing is an operation performed because of glazing and loading, dulled grains and chips are removed (crushed or fallen) with a proper dressing tool to make sharp cutting edges and simultaneously, make recesses for chips by properly extruding to grain cutting edges. The basic dressing operation consists of removal of grains and swarfloaded, generation and exposure of the new cutting edges on the cutting surface of the grinding wheel. The former is obtained by digging out the swarf and the latter is achieved by fracturing the existing abrasive grains and allowing desired protrusion of abrasive particles on the cutting surface. Both of the above operations are carried out using a diamond dresser (3 carat). A part of this work focuses on finding the optimum dressing parameters (depth of cut of the dresser and the number of passes) which gives optimum cutting condition for grinding using conventional method of grinding using diamond dresser, Water Jet Machine and Abrasive Water Jet Machine. The trial run on the conventional machine with different parameters was performed. The results obtained prove the possibility of using directly in the industrial practices.

Pottery of the late 16th — first quarter of the 18th c. from the Sofia yard of the Tobolsk Kremlin and the Upper town: comparative morphological analysis

The article presents morphological analysis of ceramic complexes from excavations in 2006 and 2017 in the city of Tobolsk. The pottery came from two areas: the Tobolsk Kremlin and the Upper town (9 Oktyabrskaya st.). Within this research, we aimed to conduct comparative analysis of morphology of the tableware from these sites to assess its similarities. From the two areas, 2261 ceramic fragments have been analyzed, and 200 vessels (counted by rims) from the late 16th c. — first quarter of the 18th c. layers have been identified. By the production technology, the dishes are non-glazed, made mainly on the pottery wheel. Hand-made ceramics have also been found in small quantity (less than 2 %). The assemblage is dominated by pot-like dishes (94.5 %). The proportion of cupped dishes is small. Other types of dishes (large pot, washbasin pot) have been found in single numbers. Based on the appearance of rims and necks, three types of pots and five types of bowls have been identified. Comparison has been made between the diameter of the mouth and the type of pot. Further examined were the frequency of occurrence of dishes with different colors and type of surface treatment, dimensions of bottoms, frequency of adding of sand to the surface of the pottery wheel. The assemblages have been compared to the late medieval ceramics of the northern, north-western and central regions of Russia, as well as the Urals and Siberia. Comparisons have been also made with the results of other studies of the Tobolsk ceramics. Statistics show that the pottery complexes are very similar to each other, both in large groups (pot-shaped and cup-shaped ware) and by other parameters (color and type of surface treatment, rim shape, mouth and bottom size, the ratio between types and diameters of pot mouths). Differences have been identified in the proportion of higher quality light gray dishes, being 2.5 times larger in the territory of the Upper town than in the Sofia yard. The difference is also expressed in proportions of the three types of pots. Type I prevails in the territory of the Upper town, and types II and III — in the Sofia court. Bowl-shaped dishes are diverse (3 types) and are present in both parts of the town. The quality light gray and black-glazed vessels of this type have been classified as tableware, partially for the lack of traces of soot. With this classification, the proportion of bowls defined as tableware constitutes 3 %. Comparison of the assemblages with the late medieval pottery from other regions of Russia revealed close analogies. But in terms of the general range of dishes, Tobolsk stands behind the cities of the European part of the country.

Dynamic derailment simulation of an empty wagon passing a turnout in the through route

Turnouts are among the weakest links of railway lines, but the derailment risk of vehicles passing the through route of a turnout is seldom considered. The potential factors affecting derailment are screened according to field investigations of a train derailment case at the through route of a turnout. A detailed wagon-turnout interaction model considering the non-uniform cross-sections of turnout rails and the interaction between adjacent wagons is developed and validated. Through numerical simulation, the dynamic performance of an empty wagon passing the through route of turnout at a low speed is studied. When the wagon passes the turnout under the continuous lateral force condition, the wheels climb onto the rail head at the switch area in the facing direction, while the derailment occurs at the frog area in the trailing direction. Moreover, the possibility of derailment of the empty wagon increases with increasing coupler force and wheel-rail friction coefficient, and with decreasing speed. To improve the safety of empty wagons in the turnout area, rail lubrication should be implemented to reduce the wheel-rail friction coefficient, and large braking forces should be avoided. Furthermore, the wheel surface condition after re-profiling requires continuous attention.

Development of novel high-shear and low-pressure grinding tool with flexible composite

ABSTRACT It is known that there are some grinding issues for difficult-to-machine materials, such as adhesion of the grinding wheel, grinding burns, and poor surface quality. In this work, a novel abrasive tool which was based on the principle of liquid body armor was developed with flexible composite to improve the grinding performance. During grinding, particles in the abrasive tool will produce a “hydro-cluster effects” to remove the micro convex of the workpiece surface in a high-shear and low-pressure manner. Rheological measurement of prepared shear thickening fluid (STF) and shear thickening abrasive fluid (STAF) showed that the prepared STF and STAF possessed superior shear thickening properties. In addition, the grinding experiments were carried out to investigate the performance of the novel abrasive tool. Surface roughness of the Inconel718 workpiece decreased from Ra 1.55 μm to Ra 0.38 μm within 90 min. The original pretreatment marks were completely eliminated and the better surface finish was achieved. The surface quality of Inconel718 was greatly improved after grinding. Experimental results verified the effectiveness of the novel high-shear and low-pressure abrasive tool. This work is quite potential to provide an alternative new abrasive tool for the grinding of difficult-to-machine materials in manufacturing industries.

Stand for accelerated tests of rail vehicles wheelsets

Tests and research can be greatly accelerated by applying a multi-point load to the test wheel. The aim of this work is to substantiate rational parameters of the stand for accelerated life tests of railway wheelsets, in which a multi-point load applies to the rolling surface of the test wheel. On the basis of the laws of the theory of elasticity, we performed analytical calculations of the contact stresses created by the rolling bodies of the load mechanism of the test stand. Research has shown that the dependence of the contact stresses on the wheel rolling surface on the ball’s diameter is nonlinear. The decrease in stress is due to an increase in the contact area. We obtained the analytical and graphical dependencies, which make it possible to evaluate the influence of the parameters of the stand for accelerated life tests of railway wheelsets on contact stresses on the wheel rolling surface, taking into account the shape and dimensions of this surface. The authors have proposed a stand design for accelerated life tests of railway wheelsets. The use of a stand with the parameters justified in this work will reduce the test duration by 10-15 times.

Visualization and analysis of wheel camber angle effect for slope traversability using an in-wheel camera

This paper visualizes and analyzes an effect of a wheel camber angle for the slope traversability in sandy terrain. An in-wheel camera developed in this work captures the wheel-soil contact phenomenon generated beneath the wheel through a transparent section of the wheel surface. The images taken by the camera are then analyzed using the particle image velocimetry. The soil flows with various wheel camber angles are analyzed with regard to the soil failure observed on the slope surface. The analysis reveals that the slope failure and soil accumulation in front of the wheel significantly affect the wheel forces and distributions of the wheel sinkage in the wheel width direction. Further, the side force of the wheel in traversing a slope decreases as the slip ratio increases because the shear stress in the slope downward direction decreases owing to the slope failure.

Wear of a Diamond Wheel during Grinding of Ceramic Balls Made of Silicon Carbide

The results of an experimental study of the effect of the mode of processing on the wear of the diamond wheel surface and on the accuracy of batch processing during diamond grinding of ceramic balls made of silicon carbide are discussed. The grinding pattern and the frequency of wheel strokes have a statistically significant effect on the maintaining of the original flat shape of the wheel, while the discrete feeding of the wheel has no direct effect on its uneven wear. The condition for minimizing the difference in the diameter of the balls within a batch and maintaining the original flat shape of the wheel will be the choice of grinding pattern with the trajectory of the balls tangent from the inside to the outer edge of the wheel, as well as minimizing the discrete feed of the wheel in the investigated range when grinding and a simultaneous increase in the wheel feed frequency to the maximum. However, the variance of the ball diameter within a batch under these conditions does not reach the minimum possible value.

Modeling of an equal-wear shape of grinding wheel when working with longitudinal feed

The paper proposes a model of an equal-wear shape of the working surface of grinding wheels operating in the self-sharpening mode, where the principles of system workability are used. It is established that to obtain engineering solutions, the wheel should be considered as a ceramic body that cuts into the ‘Voicht medium’. A disadvantage of the adopted model is that it does not consider the lag caused by strain. In addition, when grinding, the process temperature and the deformation rate are significantly higher than when the machine parts rub together. It is shown that the condition of equal wear of the wheel surface is provided by equal wear of the abrasive grains on the entire working surface, the density of the working grains on the elementary section of the contact surface. The paper presents conditions under which equal-wear shapes of wheels working with a longitudinal feed are provided.

An investigation on grinding mechanism of alumina ceramic using a grooved grinding wheel with inclined cross section

In this study, a type of the grooved grinding wheel with inclined cross section is designed based on trapezoidal beam. The grinding type of grooved grinding wheel with inclined cross section is used as a new structuring method to process alumina ceramic. The inclined cross-section groove of a grinding wheel can improve the wear-resistant properties of laser macro-structured grinding wheel. First, a pulse laser was used to ablate rectangular cross-section groove and inclined cross-section groove on two bronze-bonded diamond wheels. Second, a grinding test was performed by using the grooved grinding wheel with rectangular cross-section and grooved grinding wheel with inclined cross section. The experimental results showed that the grooved grinding wheel with inclined cross section presented a reduction of grinding forces between 18 and 31.7%, but the better surface was not obtained. In addition, the inclined cross-section groove could reduce stress concentration, thus improving the wear of the grinding wheel surface. This indicates that the grooved grinding wheel with inclined cross section has better grinding performance than the grooved grinding wheel with rectangular cross section owing to the inclined cross-section structures. This provides further evidence for a method of constructing grooved grinding wheel with inclined cross section based on trapezoidal beam design.

Забезпечення ефективності та безпеки перевезень зменшенням зносу в парі тертя колесо-рейка

У статті розглянуто питання, пов’язані із зниженням інтенсивності зносу колісних пар і рейок до прийнятних значень для підвищення безпеки залізничних перевезень; показано ефективність застосування мастильних матеріалів в парі тертя колесо - рейка. Запропоновано математичну модель розрахунків розподілів навантаження та температури по плямі контакту гребня колеса та бічної поверхнею рейки, що дозволяє отримувати миттєві значення цих величин по поверхні. Ці результати дозволять підібрати відповідні характеристики мастил, що використовуються для зменшення тертя та зносу.

Investigation of Effects of Strip Metals and Relative Sliding Speeds on Friction Coefficients by Reversible Strip Friction Tests

Friction at the interface between strips and dies is an important factor influencing the formability of strip or sheet forming. In this study, the frictional behaviors of strips at variant speeds were investigated using a self-developed strip friction test machine with a dual tension mechanism. This friction test machine, stretching a strip around a cylindrical friction wheel, was used to investigate the effects of various parameters, including sliding speeds, contact angles, strip materials, and lubrication conditions on friction coefficients at the strip–die interface. The friction coefficients at the strip–die interface were calculated from the drawing forces at the strip on both ends and the contact angle between the strip and die. A series of friction tests using carbon steel, aluminum alloy, and brass strips as the test piece were conducted. From the friction test results, it is known that the friction coefficients can be reduced greatly with lubricants on the friction wheel surface and the friction coefficients are influenced by the strip roughness, contact area, relative speeds between the strip and die, etc. The friction coefficients obtained under various friction conditions can be applied to servo deep drawing or servo draw-bending processes with variant speeds and directions.

Theoretical determination of the distribution of forces and the size of the boundaries of the contact in the interaction of the deformable drive wheel with the soil

The article presents the results of an analytical determination of the forces distribution along the length of the contact curve of the driving deformable wheel on the deformable supporting surface, and also are defined the boundaries of the contact zone. The case in a flat statement of the problem is considered. The supporting surface and the surface of the deformable wheel are represented as a continuous deformable medium. The shape of the wheel in the contact zone is represented by the circle equation, which in the contact zone is expanded in a Macloran-series. By using conditions at the boundaries of the contact zone, a system of equations is obtained from which the sizes of the contact zone are determined. The solution of these equations allows one to find expressions of the sizes of the contact zone of the deformable wheel with the deformable surface, depending on the mechanical properties of the wheel materials and the supporting surface, from the geometric dimensions of the wheel and from the loads applied to it. In addition, the results of the studies allow us to determine the analytical expression of the coefficient of rolling resistance of a deformable wheel over a deformable surface, depending on their mechanical properties, geometric parameters, and the loads applied to it.

Substantiation of work quality indicators of the universal seeds scarificator of the eastern galega (<em>Galega Orientalis</em>)

Eastern galega (Galega orientalis) contains amino acids and vitamins necessary for the normal functioning of the animal organism. In addition, it is a good precursor to many cultures. One of the drawbacks of Eastern galega is the hard shell of the seeds, which leads to increased seed consumption, a prolonged time of seedlings and an irrevocable loss of part of the sown seeds. The most affordable, simple and productive is the mechanical method of violating the tightness of the coating film of seeds. The aim of the study was to conduct comparative experiments with the existing scarifier, to create an improved design of a disk scarifier, which allows to improve the quality of seed treatment, and the theoretical justification of its structural and technological parameters. The original design of the disk scarifier on the seeds of the Eastern galega was investigated. The working bodies of the blades of the scarifier disc and their changing installation angle allows to adjust the contact angle of the seeds with the abrasive surface of the grinding wheel, thereby scratching the hard shell of the seeds without injuring them. In contrast to the used designs of scarifiers, the device under development provides for a pneumatic system for removing dust and impurities from the abrasive surface of the grinding wheel by the air flow and additional seed treatment with the microbiological preparation rhisotorfin. In the study of qualitative indicators of scarification of Eastern galega at an average moisture content of 9%, the following parameters were determined: seed germination,%; the degree of scarification,% and the degree of crushing of seeds,% with disk rotation modes - 700, 900, 1100, 1300, 1500 rpm. The studies have shown high-quality seed treatment compared to its counterpart. In the recommended range of disk revolutions of 900 ... 1100, the proposed scarifier showed a decrease in the degree of crushing of seeds by 0.2 ... 0.4%, an increase in the degree of scarification by 2 ... 3% and the degree of germination by 4 ... 5%. The use of the developed design of the scarifier in international practice will reduce the damage of the treated seeds and increase the yield of legumes.