Study on Acoustic Emission During High-Speed Grinding and Ultraprecision Grinding of Advanced Ceramics

1999 ◽  
Author(s):  
S. Gowri ◽  
Bryan K. A. Ngoi ◽  
K. Ramesh
Keyword(s):  
Residual Stress ◽  
Material Removal ◽  
High Speed ◽  
Acoustic Emissions ◽  
Ceramic Surfaces ◽  
High Speed Grinding ◽  
Grinding Conditions ◽  
Machining Productivity ◽  
Brittle Mode

Abstract The process of grinding produces characteristic acoustic emissions (AE) and the signals of AE could be used as ‘condition monitoring’ tool to understand the phenomenon involved in material removal. It has been observed that high-speed grinding of the ceramics improved machining productivity without deteriorating the surface quality of the ceramics, which is not common in the case of metals. Residual stress analysis on the machined ceramics indicated that built-in residual stress might have reduced the crack-formation. Critical grinding conditions limiting the formation of cracks on the ceramics were identified. The trend in AErms signals could be correlated to the grinding force and the grinding conditions. In case of ultraprecision machining, the ductile regime grinding of the ceramics was found out in terms of feed and depth of grinding with grinding velocity. Analysis with the SEM of machined ceramic surfaces and the AErms could reveal the occurrence of ductile regime grinding and also the transition of ductile to conventional brittle mode of material removal during grinding.

Simulation and Experiment on the Residual Stress in Super-High Speed Grinding

2010 ◽  
Vol 135 ◽  
pp. 238-242
Author(s):  
Yue Ming Liu ◽  
Ya Dong Gong ◽  
Wei Ding ◽  
Ting Chao Han
Keyword(s):  
Residual Stress ◽  
High Speed ◽  
Element Model ◽  
Residual Stress Distribution ◽  
X Ray Diffraction ◽  
Machined Surface ◽  
X Ray ◽  
High Speed Grinding ◽  
Simulation And Experiment ◽  
Cylindrical Workpiece

In this paper, effective finite element model have been developed to simulation the plastic deformation cutting in the process for a single particle via the software of ABAQUS, observing the residual stress distribution in the machined surface, the experiment of grinding cylindrical workpiece has been brought in the test of super-high speed grinding, researching the residual stress under the machined surface by the method of X-ray diffraction, which can explore the different stresses from different super-high speed in actual, and help to analyze the means of reducing the residual stresses in theory.

Ultra-High Speed Grinding Using a CBN Wheel for a Mirror-Like Surface Finish

2005 ◽  
Vol 291-292 ◽  
pp. 67-72 ◽  
Author(s):  
M. Ota ◽  
T. Nakayama ◽  
K. Takashima ◽  
H. Watanabe
Keyword(s):  
Surface Finish ◽  
High Speed ◽  
High Efficiency ◽  
Ground Surface ◽  
Machining Process ◽  
Grinding Wheel ◽  
Cbn Wheel ◽  
Ultra High Speed ◽  
High Speed Grinding ◽  
Grinding Conditions

There are strong demands for a machining process capable of reducing the surface roughness of sliding parts, such as auto parts and other components, with high efficiency. In this work, we attempted to grind hardened steel to a mirror-like surface finish with high efficiency using an ultra-high speed grinding process. In the present study, we examined the effects of the work speed and the grinding wheel grain size in an effort to optimize the grinding conditions for accomplishing mirror-like surface grinding with high efficiency. The results showed that increasing the work speed, while keeping grinding efficiency constant, was effective in reducing the work affected layer and that the grinding force of a #200 CBN wheel was lower than that of a #80 CBN wheel. Based on these results, a high-efficiency grinding step with optimized grinding conditions was selected that achieved excellent ground surface quality with a mirror-like finish.

scholarly journals Mechanism of Chip Formation Process at Grinding

2019 ◽  
Vol 297 ◽  
pp. 09002
Author(s):  
Vyacheslav Shumyacher ◽  
Sergey Kryukov ◽  
Olga Kulik ◽  
Xavier Kennedy
Keyword(s):  
Formation Process ◽  
Chip Formation ◽  
High Speed ◽  
Cutting Speed ◽  
Dimensional Accuracy ◽  
Processing Parameters ◽  
Abrasive Grain ◽  
Wave Heating ◽  
High Speed Grinding

The mechanism of chip formation process at grinding is described, which involves a high-speed interaction of abrasive grain and metal, which leads to a concentration of thermal energy in front of the dispersing element (grain), causing a locally concentrated shift in the metal microvolume. In “abrasive grain -metal” contact a dissipative structure is formed which existence is supported by exchange of energy and substance with environment. Due to shock compression of the metal microvolume with abrasive grain, shock-wave heating is realized, initiating emission of electrons ionizing the lubricating cooling fluid in the zone of formation of side micro-scratches left by abrasive. The results obtained in the course of the research can be used to explain the mechanisms of chip formation, as well as the course of the physical and mechanical processes occurring on the surface layers of the grinded workpieces. By controlling chip formation processes at high-speed grinding, by optimally selecting the appropriate ratios between cutting speed and other processing parameters, a reduction in process thermal density can be achieved, which, with the highest productivity, will allow to obtain the required quality of the surface layer of the workpieces and a given dimensional accuracy.

Surface Effects and Residual Stresses in Electrolytically Ground Steel

1962 ◽  
Vol 84 (4) ◽  
pp. 483-489 ◽  
Author(s):  
J. Frisch ◽  
R. R. Cole
Keyword(s):  
Residual Stress ◽  
Corrosion Resistance ◽  
Residual Stresses ◽  
Material Removal ◽  
Removal Rate ◽  
Stress Distributions ◽  
Electrolyte Flow ◽  
Surface Conditions ◽  
Mechanical Removal ◽  
Grinding Conditions

The effects of electrolytic grinding on surface conditions and residual stress characteristics has been experimentally investigated. Surface finish, uniformity of material removal, and corrosion resistance are found to be dependent on mechanical removal rate as determined by wheel downfeed as well as electrolyte flow rate. Downfeeds of approximately 0.002 in. in the process do not produce measurable residual stresses and therefore it was further established that electrolytic grinding with moderate downfeeds can be used in place of swab etching techniques for evaluation of residual stress distributions. The maximum residual surface stresses were found to be not more than 22,000 psi, well below the yield strength of the material and were induced during the most severe grinding conditions.

Temperatures in High Speed Grinding of TC4 with a Vitrified CBN Wheel

2011 ◽  
Vol 188 ◽  
pp. 134-138
Author(s):  
X.H. Yu ◽  
Guo Qin Huang ◽  
Cong Fu Fang ◽  
Hui Huang ◽  
H. Guo ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Material Removal ◽  
High Speed ◽  
Cbn Wheel ◽  
Grinding Speed ◽  
Grinding Parameters ◽  
High Speed Grinding ◽  
Speed Up ◽  
Vitrified Cbn Wheel ◽  
Vitrified Cbn

An investigation is reported on the temperature in grinding of titanium alloy (TC4) by using a vitrified CBN wheel at grinding speed up to 120m/s. The temperatures under different grinding parameters were measured by using a sandwiched foil thermocouple. Coupled with the SEM observations on the ground workpiece surfaces, characteristics of temperature in high speed grinding were analyzed and compared with the temperatures in grinding at normal speeds. It is found that grind speed is the most significant factor to determine temperatures, which might be associated with the increase of material removal in the plastic way at higher grinding speed.

scholarly journals Residual Stresses Distributions in Grinding of 3J33 Maraging Steel with Miniature Electroplated CBN Wheel

2019 ◽  
Vol 256 ◽  
pp. 01002 ◽  
Author(s):  
Shouguo Shen ◽  
Beizhi Li ◽  
Weicheng Guo
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Maraging Steel ◽  
Ground Surface ◽  
Stress Profile ◽  
Residual Stress Profile ◽  
Compressive Stresses ◽  
Grinding Speed ◽  
Grinding Conditions

It is well known that the residual stresses on the ground surface and the subsurface can influence the service quality of a component, such as fatigue life, tribological properties, and distortion. In this paper, an experimental investigation was conducted to determine the effects of grinding force, temperature and grinding conditions, such as grinding speed, workpiece speed and grinding depth, on the surface and in-depth residual stresses distributions induced by grinding of 3J33 maraging steel with the miniature electroplated CBN Wheels. The results show that a ‘hook’ shaped residual stress profile is generated with the maximum compressive stresses occur at the depth of 3-14 ?m below the ground surface. There is a good correlation between residual stress and cutting force, but the trend related to grinding temperature is not obvious. The main grinding parameters affecting the residual stresses distributions is grinding speed, while the workpiece speed and grinding depth have the least effect.

scholarly journals Experimental study of single cubic boron nitride grains in the ultrasound-assisted high-speed grinding

2017 ◽  
Vol 9 (2) ◽  
pp. 168781401769354 ◽  
Author(s):  
Dao-hui Xiang ◽  
Zhong-yun Liu ◽  
Zhi-kun Zhou ◽  
Yun-long Yao
Keyword(s):  
Experimental Study ◽  
Boron Nitride ◽  
Surface Quality ◽  
High Speed ◽  
Cubic Boron Nitride ◽  
Grinding Force ◽  
Abrasive Particles ◽  
Ultrasonic Assisted ◽  
High Speed Grinding

The kinematic characteristics, grinding force, surface quality of workpiece surface, and wear of abrasive particles were studied by theoretical analysis and experimental study on the single cubic boron nitride abrasive particles under ultrasonic-assisted high-speed grinding. Under the condition of the same grinding parameters, the motion characteristics and the grinding forces of the two machining modes of general grinding and ultrasonic-assisted grinding are compared and analyzed. Research shows that the ultrasonic vibration is applied in the common external circular grinding on grinding particle movement characteristics changed obviously, grinding particle trajectory of variable length, cutting groove width wider, thereby improving the grinding efficiency and the grinding removal rate; ultrasonic assisted under high speed grinding, the grinding force is higher than that of common grinding force is small, efficiency of grinding under ultrasonic processing mode is much higher than ordinary grinding, the surface quality of the workpiece has improved markedly.

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