The Development of Nanocrystalline CBN for Enhanced Superalloy Grinding Performance

1997 ◽  
Vol 119 (1) ◽  
pp. 110-117 ◽  
Author(s):  
Y. Ichida ◽  
K. Kishi
Keyword(s):  
Wear Rate ◽  
Grinding Wheel ◽  
Grinding Wheels ◽  
Wear Rates ◽  
Grinding Performance ◽  
Wide Range ◽  
Edge Distribution ◽  
Order Of Magnitude ◽  
Life Analysis ◽  
Magnitude Increase

CBN grinding wheels are increasingly used on a wide range of engineering materials. This paper compares the grinding performance of monocrystalline (M-CBN) and polycrystalline (P-CBN) abrasives with a newly developed nanocrystalline (N-CBN) abrasive, when grinding nickel-based superalloys. The N-CBN grits possess average crystal grain diameters less than 1 μm compared to average primary grain diameters of 2.3 μm for P-CBN. It was found that the nanocrystalline CBN grits possess higher fracture strength which give reduced wear rates and yield an order of magnitude increase in grinding wheel life. Analysis of the cutting edge distribution shows that the reduced wear rate of N-CBN is due to the predominance of a micro-fracturing mode of abrasive wear. The size of this micro-fracturing is considerably smaller in N-CBN than in P-CBN.

Development of Vitrified Bond CBN Wheel for Internal Precision Grinding of the Air-Conditioner Compressor Piston Hole

2006 ◽  
Vol 304-305 ◽  
pp. 29-32 ◽  
Author(s):  
Hang Gao ◽  
Y.G. Zheng ◽  
W.G. Liu ◽  
Jian Hui Li
Keyword(s):  
Cost Effective ◽  
Grinding Wheel ◽  
Manufacturing Cost ◽  
Air Conditioner ◽  
Grinding Wheels ◽  
Precision Grinding ◽  
Grinding Performance ◽  
Compressor Piston ◽  
Vitrified Bond ◽  
Cbn Grinding Wheel

Manufacturing of vitrified bond CBN wheels for internal precision grinding of the air-conditioner compressor piston hole is still big challenge to all of the domestic manufacturers. Recently, by choosing pre-melting mixed CBN abrasives and a proper sintering process, a cost-effective method was conceived to produce grinding wheels of comparative quality. The grinding performance of wheels was evaluated with a series of internal precision grinding of compressor piston hole. Experimental results show that the vitrified bond CBN grinding wheel produced by this method has better grinding performance, and can be substitute to the same type of grinding wheels imported. But the manufacturing cost is only 60% of the wheel imported according to estimation.

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.

Development on Micro Precision Truing Method of ELID-Grinding Wheel (2nd Report: Application to Edge Sharpening of Large Wheel)

2005 ◽  
Vol 291-292 ◽  
pp. 213-220 ◽  
Author(s):  
Shao Hui Yin ◽  
Wei Min Lin ◽  
Yoshihiro Uehara ◽  
Shinya MORITA ◽  
Hitoshi Ohmori ◽  
...  
Keyword(s):  
Surface Quality ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Wheels ◽  
Elid Grinding ◽  
Diamond Grinding ◽  
Grinding Performance ◽  
Profile Accuracy ◽  
Large Wheel ◽  
Edge Sharpening

In V-groove ELID grinding process, to achieve optimal grinding performance and satisfactory surface quality and profile accuracy, metal bonded diamond grinding wheels need to be carefully sharpened. In this paper, we applied the proposed new micro-truing method consisting of electro-discharge truing and electrolysis-assisted mechanical truing to sharpen the edge of large grinding wheels. The minimum wheel tip radiuses of 6.3 and 8.5µm were achieved for the #4000 and #20000 grinding wheels. The truing mechanisms and sharpening performance are also discussed.

Effect of Novel Grinding Wheels on Grinding Performance

2013 ◽  
Vol 405-408 ◽  
pp. 3302-3306
Author(s):  
Ming Yi Tsai ◽  
Shi Xing Jian ◽  
J. H. Chiang
Keyword(s):  
Surface Roughness ◽  
Pure Water ◽  
Minimum Quantity Lubrication ◽  
Grinding Wheel ◽  
Grinding Temperature ◽  
Grinding Wheels ◽  
Wheel Wear ◽  
Grinding Performance ◽  
Conventional Grinding ◽  
Removal Processes

Grinding, a technique for removing abrasive materials, is a chip-removal process that uses an individual abrasive grain as the cutting tool. Abrasive material removal processes can be very challenging owing to the high power requirements and the resulting high temperatures, especially at the workpiece-wheel interface. This paper presents a novel system that uses graphite particles impregnated in an aluminum oxide matrix to form a grinding wheel. This study specifically investigated grinding wheels with a graphite content of 0.5 wt%. The new grinding wheel was compared with conventional grinding wheels by comparing the factors of grinding performance, such as surface roughness, morphology, wheel wear ratio, grinding temperature, and grinding forces, when the wheels were used under two different coolant strategiesdry and with minimum quantity lubrication (MQL) using pure water. This study found that there is a considerable improvement in the grinding performance using graphite-impregnated grinding wheels over the performance obtained using conventional grinding wheels. The use of 0.5 wt% graphite provided better surface roughness and topography, lower grinding temperature, and decreased force; in addition, wheel consumption was lower, resulting in extended wheel life.

Defect Structures in Diamond Composite Coated Cemented Tungsten CarbideSubstrates

2011 ◽  
Vol 325 ◽  
pp. 339-344 ◽  
Author(s):  
Jim N. Boland ◽  
Xing S. Li ◽  
D. Hay ◽  
Colin M. MacRae ◽  
S. Elbracht ◽  
...  
Keyword(s):  
Wear Rate ◽  
Poor Quality ◽  
Wear Testing ◽  
Grinding Wheel ◽  
Sem Images ◽  
Volume Percentage ◽  
X Ray ◽  
Wear Rates ◽  
Valid Test ◽  
The Difference

Variability in the abrasive wear of PCD coatings on cemented WC substrates has been investigated. Six samples of PCD coated carbides were tested in a wear testing rig. The PCD coated element was used to turn an industry standard vitrified bonded corundum grinding wheel. The wear rate was measured as the weight loss of the cutting element per cubic metre of grinding wheel machined during the test. Two grades of cutting elements were observed. One grade had wear rates between 6 and 7.3 g/m³ but of the three poor quality samples, only one valid test was made realising wear rate of ~7,800 g/m³. The microstructures of the samples were studied using SEM, X-ray imaging, neutron diffraction and XRD. SEM images revealed differences in the volume percentage of diamonds in the two grades and the XRD scans highlighted the variable distribution of the diamond phase in the coating. Estimates of the residual stresses in a good and poor quality samples indicated significantly higher compressive stresses in the good quality versus poor quality coating. These results have revealed two extremes in the wear rates of these PCD coated carbides. It is suggested that the difference in diamond content between the two grades is not sufficient to account for the 3 orders-of-magnitude difference in the observed wear rates. However, the presence of intrusive veins of carbide material in the coatings, especially around the curved cutting tip, suggested that the macroscopic defects observed in the x-ray and SEM images were the major cause of the high wear rates in the poor quality sample.

The dry wear of steels I. The general pattern of behaviour

1965 ◽  
Vol 257 (1077) ◽  
pp. 31-50 ◽  
Keyword(s):  
Wear Rate ◽  
General Framework ◽  
General Pattern ◽  
Sliding Speed ◽  
Wear Process ◽  
Wear Rates ◽  
Mild Wear ◽  
Wide Range ◽  
A Minor ◽  
Severe Type

The broad trends of the wear rate when steels rub together without lubrication have been studied by means of pin and ring apparatus. Over a wide range of load (10 g to 40 Kg) and sliding speed (1.7 to 266 cm/s) the wear process at equilibrium is either of a severe type, producing coarse metallic debris, or of a mild type, producing fine oxidized debris. The corresponding wear rates differ by more than two orders of magnitude. Transitions from one wear process to the other occur at well-defined loads and for soft steels a basic pattern, comprising three transitions, has been identified: T1 a change from mild wear to severe at light loads; T2, a change from severe wear back to mild at higher loads; T3, a minor change in the mild wear rate at loads above T2, characterized by divergent wear rates of the pin and ring. The way in which this pattern varies with the sliding speed and with the composition and hardness of the steel is traced and the findings of previous investigations co-ordinated in the general framework.

One Order of Magnitude Increase of Triplet State Lifetime Observed in Deprotonated Form Selenium Substituted Uracil

2021 ◽  
Author(s):  
Peipei Jin ◽  
Xueli Wang ◽  
Haifeng Pan ◽  
Jinquan Chen
Keyword(s):  
Nucleic Acids ◽  
Triplet State ◽  
Deprotonated Form ◽  
X Ray ◽  
X Ray Crystallography ◽  
Wide Range ◽  
Order Of Magnitude ◽  
Medical Therapies ◽  
Magnitude Increase

Selenium nucleic acids possess unique properties and have been demonstrated to have a wide range of applications such as DNA X-ray crystallography and novel medical therapies. Yet, as a heavy...

Tribology of Insulation Materials Within Implantable Cardioverter-Defibrillator Leads

2012 ◽  
Author(s):  
Charles Wilson ◽  
Adam Himes
Keyword(s):  
Wear Rate ◽  
Implantable Cardioverter Defibrillator ◽  
Failure Modes ◽  
Wear Rates ◽  
Cardioverter Defibrillator ◽  
Insulation Materials ◽  
Icd Leads ◽  
Order Of Magnitude ◽  
In Vivo Loading

Insulation wear in implanted cardioverter-defibrillator (ICD) leads may result in serious failure modes, including inappropriate or missing therapy. Tests performed on a custom apparatus developed to simulate in-vivo loading showed order of magnitude differences in specific wear rate between materials commonly used in ICD leads. Wear rates were also dependent on load, suggesting that design and application differences may further differentiate performance between materials.

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

2016 ◽  
Vol 231 (4) ◽  
pp. 621-632 ◽  
Author(s):  
Krzysztof Nadolny ◽  
Witold Habrat
Keyword(s):  
Sol Gel ◽  
Active Surface ◽  
Positive Influence ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Wheels ◽  
Abrasive Grains ◽  
Wide Range ◽  
Internal Cylindrical Grinding ◽  
Different Diameters

This article offers an overview of 14 grinding wheel construction modifications used in the peripheral grinding of flat-shaped internal and external cylindrical surfaces, when grinding wheels made of conventional abrasive grains are used (Al2O3, sol-gel alumina, SiC, etc.). The text contains characteristics of grinding wheels with mixed grains, glass-crystalline bond, a centrifugal provision of the coolant into the grinding zone, aggregate grains, zones of different diameters, radial rough grinding zone, extended finish grinding segments, active surface macro- and micro-discontinuities, as well as multiporous, impregnated (self-lubricating), sandwich, sectional and segment grinding wheels. Each of the presented structural modifications was 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 allows for their proper selection depending on the required criteria of effective evaluation and taking into account the specific characteristics of conventional abrasive 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 A Novel Optimization Design Method of Form Grinding Wheel for Screw Rotor

2019 ◽  
Vol 9 (23) ◽  
pp. 5079 ◽  
Author(s):  
Zongmin Liu ◽  
Qian Tang ◽  
Ning Liu ◽  
Pinghua Liang ◽  
Wei Liu
Keyword(s):  
Optimization Design ◽  
Design Method ◽  
Empirical Method ◽  
Grinding Wheel ◽  
Grinding Wheels ◽  
Grinding Performance ◽  
Form Grinding ◽  
Screw Rotor ◽  
Screw Rotors ◽  
Profile Accuracy

The profile accuracy of screw rotors plays a vital role in stabilizing the meshing operation between mated rotors. Such stability can minimize the vibration and noise, as well as improve the sealing performance and wear resistance. This is the main reason why form grinding is extensively applied as a finishing process to maintain high screw rotor profile accuracy. Since the installation parameters for form grinding wheels affect both the grinding wheel profile accuracy and grinding performance, it is essential to obtain reasonable installation parameters to guarantee the high precision and good grinding performance of form grinding wheels. In this paper, a novel optimization design method for form grinding wheels for screw rotors has been proposed. For the first time, the relationship between the grinding wheel installation parameters and profile accuracy is established to evaluate the grinding performance. A parameterized program has been designed based on space engagement theory. The characteristics of the contact line and profile features of form grinding wheels under different installation parameters have been investigated. Then, the proposed method was employed to select the correct range of installation parameters. To validate the proposed method, a set of experiments, including the manufacture and measurement of several screw rotors, was carried out. The results reveal that the precision of the screw profile is significantly improved compared with the empirical method, thus showing the effectiveness of the proposed method.

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