scholarly journals MODELING THE INFLUENCE OF METAL PHASE IN DIAMOND GRAINS ON SELF-SHARPENING OF GRINDING WHEELS ON CERAMIC BONDS

2021 ◽  
pp. 92-101
Author(s):  
Vladimir Fedorovich ◽  
Dmitri Fedorenko ◽  
Ivan Pyzhov ◽  
Yevgeniy Ostroverkh
Keyword(s):  
Metal Phase ◽  
Hard Alloys ◽  
Theoretical Studies ◽  
Superhard Materials ◽  
Grinding Wheels ◽  
High Resource ◽  
Critical Stresses ◽  
Synthetic Diamonds ◽  
Determining Factor ◽  
Bearing Layer

The article presents the results of theoretical studies using finite element modeling, which made it possible to determine the rational characteristics of diamond wheels based on ceramic and polymer bonds. The effect of the parameters of the diamond-bearing layer on the change in its stress-strain state in the process of microcutting of hard alloys and superhard materials has been studied. It is established that the determining factor in the occurrence of critical stresses during grinding is the temperature in the cutting area, the increase of which in the presence of metal phase inclusions in diamond grains with high values of thermal expansion coefficient can lead to destructive stresses in grains and, consequently, their premature destruction. It is advisable to use diamond grains with a minimum content of metal phase and the use in the manufacture of synthetic diamonds solvent metals with a low value of this coefficient, which will significantly increase the use of potentially high resource diamond grains.

Potential for improving efficiency of the internal cylindrical grinding process by modification of the grinding wheel structure—Part II: Grinding wheels made of superabrasive grains

2016 ◽  
Vol 231 (4) ◽  
pp. 813-823 ◽  
Author(s):  
Krzysztof Nadolny ◽  
Witold Habrat
Keyword(s):  
Cubic Boron Nitride ◽  
Positive Influence ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Wheels ◽  
Structural Modifications ◽  
Synthetic Diamonds ◽  
Wide Range ◽  
Internal Cylindrical Grinding ◽  
Different Diameters

This article offers an overview of 11 grinding wheel construction modifications used in the peripheral grinding of flat, shaped, internal, and external cylindrical surfaces, when grinding wheels made of superabrasive grains are used (natural and synthetic diamonds, as well as mono- and microcrystalline cubic boron nitride). The text contains characteristics of grinding wheels with: bubble corundum grains, glass-crystalline bond, conic chamfer, zones of different diameters, a centrifugal provision of the coolant into the grinding zone, aggregate grains, zone-diversified structure, as well as impregnated (self-lubricating), multiporous, segment and “intelligent” grinding wheels. Each of the presented structural modifications were described by giving construction scheme, used abrasive grains, range of applications, advantages as well as disadvantages. Modifications of the grinding wheel construction allow for effective improvement of both the conditions and the results of the grinding process. A wide range of the known modifications allow for their proper selection depending on the required criteria of effective evaluation and taking into account the specific characteristics of superabrasive grains. As a result, it is possible to obtain positive influence on a number of technological factors of the grinding process. The described modifications of the grinding wheel structure can be also an inspiration and the basis for creating new solutions in this field.

scholarly journals DEVELOPMENT OF LOW-MELTING GLASSCERAMIC BONDS FOR HIGH RESOURCE DIAMOND-ABRASIVE TOOLS

2021 ◽  
pp. 103-112
Author(s):  
Olena Fedorenko ◽  
Larysa Yashchenko ◽  
Dmytro Fedorenko ◽  
Volodymyr Fedorovych ◽  
Oleksandr Koniev
Keyword(s):  
Service Life ◽  
Pore Structure ◽  
Glass Ceramic ◽  
Open Structure ◽  
Working Layer ◽  
High Resource ◽  
Large Pore ◽  
Abrasive Tools ◽  
Bearing Layer ◽  
Diamond Abrasive

Research is aimed at creating high-resource diamond-abrasive tools with a large-pore structure of the working layer, the use of which reduces the occurrence of grinding defects when processing materials sensitive to overheating. The formation of an open structure of the working layer ensures effective chip removal, which excludes a decrease in the сutting ability of the tool due to contamination with grinding sludge and creates favorable conditions for intensifying the processing of materials when using high-speed cutting modes. As part of the research, low-melting glass-ceramic binders for diamond-abrasive tools have been developed, which make it possible to increase the tool service life  due to the prevention of diamond grains premature destruction and the creation of a large-pore open structure of the working layer. Using a set of calculated data about the main characteristics of glass compositions by factor planning means, the dependences «composition - properties» were determined and the area of optimal compositions of glass-ceramic bonds was established, which ensure sintering of a diamond-containing composite at a temperature of 550–650 °C. The efficiency of the use of alumino-silicate microspheres of technogenic origin as a structure-forming filler providing the formation of a large-pore structure is shown. The features of the chemical and phase composition of the technogenic spheres recovered from the fly ash of the Krivoy Rog TPP have been determined. It has been established that when the diamond-bearing layer of the tool is sintered in the shell of the ash spheres, crystalline new formations with high hardness (hercynite, mullite, maghemite, spinel) are formed. Using ash spheres and developed low-melting binders, which include up to 30 mass. % of glass waste, the laboratory samples of diamond-containing composites with open porosity of 45-50% were made. Studies of their microstructure and morphological features made it possible to determine the pore size (130-200 μm) and establish that during grinding, partial destruction of ash spheres occurs with the formation of additional cutting elements, which increases the tool cutting ability. The research results indicate the advisability of using the proposed approach for selection of the diamond-ceramic composite components and the modes of heat treatment of the diamond-bearing layer when creating a tool. This approach will significantly expand the possibilities of manufacturing large-pore diamond-abrasive tools with a high service life at minimal material costs and will improve the processing of parts made of difficult-to-machine materials.

Influence of Chemical Composition of Tough-to-Machine Materials on Grinding Technologies

2017 ◽  
Vol 265 ◽  
pp. 793-799
Author(s):  
T.N. Ivanova
Keyword(s):  
Chemical Composition ◽  
Chemical Elements ◽  
Grinding Wheels ◽  
Surface Layers ◽  
High Quality ◽  
Synthetic Diamonds ◽  
Machine Steel ◽  
Steel Grades ◽  
Quality Surface ◽  
High Quality Surface

The main purpose of processing of tough-to-machine materials is improving of cutting process of steels with different physicochemical properties and alloying by means of various chemical elements in combination with heat treatment. Producing of high quality surface layers depends on properties of material used to make details, that is why reasons of tough machining were identified: influence of chemical composition and resulting structure. The studies of grinding of tough-to-machine materials were undertaken by means of grinding wheels made from synthetic diamonds as they are most resistant and highly-productive. Based on the studies recommendations for using of characteristics of grinding wheels and tough-to machine steel grades.

Error Size of the Helix (screw) Groove by Grinding

2011 ◽  
Vol 496 ◽  
pp. 19-24
Author(s):  
Karel Jandečka
Keyword(s):  
Present Article ◽  
Analytical Method ◽  
Grinding Wheel ◽  
Theoretical Studies ◽  
Spiral Groove ◽  
Grinding Wheels ◽  
Know How ◽  
Foreign Companies ◽  
Grant Agency ◽  
Helical Grooves

This paper presents further results in addressing this issue and builds upon the results obtained within the project GACR No. 101/07/0751 (research was supported by Czech Grant Agency), and the findings and information obtained from grant project GACR No. 101/05/2562. The problems are oriented to the production and sharpening of rotary tools, especially because all the know-how is owned by foreign companies. The main chapter is devoted to "Solution of the dependance of undercutting of the helical grooves on the grinding wheel diameter, its thickness and depth of the cut" at zero thickness of the grinding wheel. This method is an original analytical method for calculating the undercutting and is a part of the theoretical studies of the grinding helix slot. Then follows a passage, which defines the actual width of the spiral groove profiles at various grinding wheels. The present article summarizes only part of a broad range of problems in the area.

scholarly journals Multi-Objective Optimization of the Dressing Parameters in Fine Cylindrical Grinding

2019 ◽  
Author(s):  
Irina Stefanova Aleksandrova
Keyword(s):  
Utility Function ◽  
Ground Surface ◽  
Grit Size ◽  
Grinding Wheel ◽  
Multi Objective Optimization ◽  
Optimum Conditions ◽  
Grinding Wheels ◽  
System Parameters ◽  
Synthetic Diamonds ◽  
Generalized Utility

The optimum conditions of dressing grinding wheels determined and recommended in the literature are valid only for particular types and tools of dressing and grinding. In this paper an attempt has been made to optimize the dressing system parameters in fine cylindrical grinding. To define the optimum values of dressing process variables (radial in-feed of diamond roller dresser , dressing speed ratio , dress-out time , diamond roller dresser grit size/grinding wheel grit size ratio , type of synthetic diamonds and direction of dressing) a multi-objective optimization has been performed based on genetic algorithm. In the capacity of optimization parameter a generalized geometric-mean utility function has been chosen which appears to be a complex indicator characterizing the roughness and accuracy of the ground surface, grinding wheel lifetime and the manufacturing net costs of grinding operation. The optimization problem has been solved in the following sequence: 1) a model of the generalized utility function has been created reflecting the complex effect of dressing system parameters; 2) the optimum conditions of uni-directional and counter-directional dressing of aluminium oxide grinding wheels by experimental diamond roller dressers of synthetic diamonds of АС32 and АС80 types and different grit size have been determined at which the generalized utility function has a maximum; 3) Pareto optimum solution has been found (frd=0.2 mm/min; qd=0.8; td=4.65 s; qg=2.56), which guarantees the best combination between roughness and deviation from cylindricity of the ground surface, grinding wheel lifetime and the manufacturing net costs of grinding operation.

scholarly journals The Influence of Chemical Composition of Tough-to-Machine Steels on Grinding Technologies

2018 ◽  
Vol 26 (3) ◽  
pp. 172-177
Author(s):  
Tanyana N. Ivanova ◽  
Aleksandr I. Korshunov ◽  
Pavol Božek
Keyword(s):  
Chemical Composition ◽  
Chemical Elements ◽  
Cutting Speed ◽  
Grinding Wheels ◽  
Surface Layers ◽  
Heating And Cooling ◽  
Synthetic Diamonds ◽  
Motion Speed ◽  
Steel Grades ◽  
Heat Processes

Abstract The main purpose of processing of tough-to-machine materials is improving of cutting process of steels with different physicochemical properties and alloying by means of various chemical elements in combination with heat treatment. Producing of high quality surface layers depends on properties of material used to make details, that is why reasons of tough machining were identified: influence of chemical composition and resulting structure. The studies of grinding of tough-to-machine materials were undertaken by means of grinding wheels made from synthetic diamonds as they are most resistant and highly-productive. Based on the studies recommendations for using of characteristics of grinding wheels and tough-to machine steel grades are given. Research on heat processes during grinding allows us to determine patterns showing how cutting speed, detail motion speed, area and action period of contact influence temperature and speed of heat processes in surface layers as well as depth of heating. These patterns also give the chance to show interrelation between temperature and rate of heating and cooling. This gives an opportunity to predict state of structure of surface layer of details made of tough-to-machine steels under different machining conditions reasonably.

scholarly journals Ceramic-matrix composite materials for the diamond abrasive tools manufacture

2017 ◽  
Vol 117 ◽  
pp. 212-224
Author(s):  
D. O. Fedorenko ◽  
V. A. Fedorovich ◽  
E. Yu. Fedorenko ◽  
K. B. Daineko
Keyword(s):  
Ceramic Matrix Composite ◽  
Ceramic Matrix ◽  
Abrasive Tool ◽  
Simulation Experiments ◽  
High Resource ◽  
Ceramic Bond ◽  
Abrasive Tools ◽  
The Given ◽  
Bearing Layer ◽  
Diamond Abrasive

The results of the development of high-resource ceramic diamond abrasive tool, the design of which was carried out using computer simulation of processes, that accompanying its manufacturing and grinding in the mode of rational self-sharpening, is presented. According to the results of simulation experiments, the composition of the diamond-bearing layer was developed and the instrument with the use of a low-melting ceramic bond with the given properties were made.

scholarly journals Multi-Objective Optimization of the Dressing Parameters in Fine Cylindrical Grinding

2019 ◽  
pp. 87-102 ◽  
Author(s):  
Irina Stefanova Aleksandrova
Keyword(s):  
Utility Function ◽  
Ground Surface ◽  
Grit Size ◽  
Grinding Wheel ◽  
Multi Objective Optimization ◽  
Optimum Conditions ◽  
Grinding Wheels ◽  
Multi Objective ◽  
Synthetic Diamonds ◽  
Generalized Utility

The optimum conditions for dressing grinding wheels determined and recommended in the literature are valid only for particular types and tools of dressing and grinding. In this paper, an attempt has been made to optimize the dressing process parameters in fine cylindrical grinding. To define the optimum values of the dressing process variables (radial feed rate of diamond roller dresser frd , dressing speed ratio qd , dress-out time td , diamond roller dresser grit size/grinding wheel grit size ratio qg , type of synthetic diamonds and direction of dressing), a multi-objective optimization has been performed based on a genetic algorithm. In the capacity of the optimization parameter, a generalized geometric-mean utility function has been chosen, which appears to be a complex indicator characterizing the roughness and accuracy of the ground surface, the grinding wheel lifetime and the manufacturing net costs of the grinding operation. The optimization problem has been solved in the following sequence: 1) a model of the generalized utility function has been created reflecting the complex effect of the dressing system parameters; 2) the optimum conditions of uni-directional and counter-directional dressing of aluminium oxide grinding wheels by experimental diamond roller dressers of synthetic diamonds of АС32 and АС80 types and different grit size at which the generalized utility function has a maximum have been determined; 3) a Pareto optimum solution has been found (frd = 0.2 mm/min; qd = 0.8; td = 4.65 s; qg = 2.56), which guarantees the best combination between the roughness and the deviation from cylindricity of the ground surface, the grinding wheel lifetime and the manufacturing net costs of the grinding operation.

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