Features of Using Metal Coatings on Diamond Grains in Electrically Conductive Grinding Wheels When Machining Polycrystalline Superhard Materials

2020 ◽  
pp. 44-52
Author(s):  
Anatoliy Grabchenko ◽  
Vladimir Dobroskok ◽  
Yevheniy Ostroverkh ◽  
Vladimir Fedorovich ◽  
Larisa Pupan
Keyword(s):  
Superhard Materials ◽  
Grinding Wheels ◽  
Electrically Conductive ◽  
Metal Coatings

scholarly journals Grinding efficiency and profile accuracy of diamond grinding wheels dressed with wire electrical discharge conditioning (WEDC)

2021 ◽  
Author(s):  
Ali Zahedi ◽  
Jahangir Khosravi ◽  
Bahman Azarhoushang
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Wear Behavior ◽  
Process Time ◽  
Grinding Wheel ◽  
Grinding Wheels ◽  
Electrically Conductive ◽  
Plunge Grinding ◽  
Specific Grinding Energy ◽  
Diamond Grinding

AbstractSuper abrasive diamond grinding wheels are the most promising tools for the precision machining of advanced ceramics and carbide materials. However, the efficiency of conventional conditioning of these tools is limited owing to high dressing tool wear, long process time, low form flexibility, and induced damage to the abrasive grains. Wire electrical discharge machining (WEDM) is an alternative method for conditioning of superabrasive grinding wheels with electrically conductive bonding materials. In this study, cylindrical plunge grinding of an alumina ceramic with a resin-bonded diamond grinding wheel is investigated. The assigned type of resin bond contains copper particles and is accordingly electrically conductive for wire electrical discharge conditioning (WEDC). Conventional (mechanical) and WEDC methods are used for generating the same profile on two similar diamond grinding wheels. As a result, the specific grinding energy was reduced up to 26% and 29% during rough and finish plunge grinding, respectively. Reduced specific grinding energy and forces, along with more effective grain protrusion and sharpness by using WEDC for profiling of grinding wheels, have contributed positively to the ground surface conditions despite the relatively rougher wheel surface topography in comparison to the conventional profiling. The more considerable reduction in the mean roughness depth (Rz) than in the arithmetical mean roughness value (Ra) (11% smaller Rz values in WEDC versus mechanical conditioning) verifies that the workpiece surface underwent less surface degradation in case of WEDC because of smaller grinding forces. Furthermore, the profile wear behavior of the workpiece ground with the WED conditioned grinding wheel was superior to the conventionally conditioned one.

Simulation of Grinding Process of Polycrystalline Superhard Materials

2013 ◽  
Vol 581 ◽  
pp. 217-223 ◽  
Author(s):  
Anatoly I. Grabchenko ◽  
Vladimir A. Fedorovich ◽  
Ivan Pyzhov ◽  
Valery Fadeev ◽  
Eugene Babenko ◽  
...  
Keyword(s):  
New Technologies ◽  
Experimental Studies ◽  
Theoretical Research ◽  
Superhard Materials ◽  
Metal Coatings ◽  
Scientific Hypothesis ◽  
Diamond Powders ◽  
Metal Bonds ◽  
Diamond Abrasive

The results of investigation in order to increase the efficiency of using diamond-abrasive and edge tool made of superhard materials (SHM) on the basis of 3D methodology of complex research of the interrelated processes of their manufacturing and operation are presented. Creation of 3D simulation methodology of processes of sintering of abrasive-diamond tools and processes of grinding of edge SHM tools with their application allows us to increase considerably the reliability of obtained results, to reduce the extent of experimental studies for determination of optimum conditions for grinding and to develop new technologies, tools and equipment. The scientific hypothesis about the expediency of using diamond powders with thick metal coatings in diamond-abrasive tools on metal bonds are proposed and proved on the basis of theoretical research. The research results are implemented as a number of grinding techniques with controllable cutting relief of the wheels and devices which realize them. Using the results of the research makes it possible to increase the reliability of the edged tool made of SHM as far back as at the stage of its sharpening.

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.

Cryogenic atomic force microscopy

1991 ◽  
Vol 49 ◽  
pp. 54-55
Author(s):  
K. A. Fisher ◽  
M. G. L. Gustafsson ◽  
M. B. Shattuck ◽  
J. Clarke
Keyword(s):  
Room Temperature ◽  
Rapid Freezing ◽  
Cryogenic Temperatures ◽  
Soft Or ◽  
Electrically Conductive ◽  
Force Microscopy ◽  
Flexible Molecules ◽  
Advantages And Disadvantages ◽  
Atomic Force ◽  
Chemical Perturbation

The atomic force microscope (AFM) is capable of imaging electrically conductive and non-conductive surfaces at atomic resolution. When used to image biological samples, however, lateral resolution is often limited to nanometer levels, due primarily to AFM tip/sample interactions. Several approaches to immobilize and stabilize soft or flexible molecules for AFM have been examined, notably, tethering coating, and freezing. Although each approach has its advantages and disadvantages, rapid freezing techniques have the special advantage of avoiding chemical perturbation, and minimizing physical disruption of the sample. Scanning with an AFM at cryogenic temperatures has the potential to image frozen biomolecules at high resolution. We have constructed a force microscope capable of operating immersed in liquid n-pentane and have tested its performance at room temperature with carbon and metal-coated samples, and at 143° K with uncoated ferritin and purple membrane (PM).

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