scholarly journals Flat grinding effectiveness increase due to rational work cycle use

2020 ◽  
Vol 2020 (9) ◽  
pp. 7-11
Author(s):  
Yuriy Zubarev ◽  
Alexsandr Priyomyshev
Keyword(s):  
Hard Alloy ◽  
Labor Productivity ◽  
High Speed ◽  
Work Cycle ◽  
High Speed Grinding ◽  
Grinding Machines ◽  
Production Areas

A possibility for machinery billet machining effectiveness increase at the expense of the use of high-speed grinding machines operated in an automated cycle of machining mode changes is considered. It allows performing operations of roughing and then finishing ensuring the required accuracy and quality of surfaces worked. The application of high-speed force grinding allows rejecting rough and finish preliminary milling and, in such a way, decreasing the number of machine equipment, hard-alloy cutters, production areas and increasing labor productivity.

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.

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.

Research on Heat Transfer and Calculation Method of Workpiece Surface Temperature in High Speed Grinding

2011 ◽  
Vol 325 ◽  
pp. 28-34
Author(s):  
Bei Zhi Li ◽  
Da Hu Zhu ◽  
Zhen Xin Zhou ◽  
Jing Zhu Pang ◽  
Jian Guo Yang
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
High Speed ◽  
Removal Rate ◽  
Convective Heat Transfer Coefficient ◽  
Calculation Model ◽  
Grinding Wheel ◽  
Workpiece Surface ◽  
High Speed Grinding

The surface quality of workpiece depends largely on workpiece surface temperature in grinding. The key parameters on workpiece surface temperature calculation model have been researched and the calculation model constructed in this paper, including the convective heat transfer coefficient (CHTC) (hf), heat flux (qch) and the grain contact half-width (r0) which are assumed to be constant in workpiece surface temperature model given by Rowe. And the improved Rowe model has been proposed (Rowe/Li model) which not only involves the grinding process parameters such as the speed of wheel and workpiece, but also the geometric parameters of workpiece, grinding wheel and abrasive. The experimental results of the surface temperature in high-speed grinding are very close to the results by Rowe / Li model. Relative to the Rowe model, the obtained surface temperature by Rowe / Li model has decreased by about 35-40%. Under the conditions of the same material removal rate, high-speed grinding, namely, increasing wheel speed can effectively reduce the surface temperature and improve the grinding quality.

New Liquid Transfer Active Balancing System Using Compressed Air for Grinding Machine

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Pan Xin ◽  
Wu Haiqi ◽  
Gao Jinji ◽  
Wang Weimin
Keyword(s):  
High Speed ◽  
Gas Pressure ◽  
Compressed Air ◽  
Grinding Wheel ◽  
Active Balancing ◽  
High Speed Grinding ◽  
Liquid Transfer ◽  
Grinding Machines ◽  
Grinding Machine

Grinding wheel unbalance will result in vibrations of grinding machines and affect the quality and precision of workpieces. Therefore, a balancing system is necessary for grinding machines to lower the vibrations caused by unbalance. In this study, a liquid transfer active balancing system, in which the balancing liquid was forced by compressed air to transfer between opposite chambers, was applied to the high-speed grinding spindle. The requirements of gas pressure and linearity of balancing ability were analyzed to confirm the feasibility of the proposed device. In addition, an active balancing experiment was also carried out efficiently during the operation.

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.

Experimental Investigation and Improvement of Dynamic Performance of High-Speed Grinding Machine

2010 ◽  
Vol 156-157 ◽  
pp. 1609-1612 ◽  
Author(s):  
Xiao Long Shen ◽  
Cheng Gao Ren ◽  
Zhi Mou Pi ◽  
Dai Li Zhu
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Power Spectra ◽  
Weak Links ◽  
Machining Accuracy ◽  
Variable Speed ◽  
High Speed Grinding ◽  
Improvement Measures ◽  
Grinding Machine

Design of the dynamic performance of a machine tool is an effective approach to improve the machining accuracy. In this paper, the dynamic performance of high-speed cylindrical grinder has been studied systematically to improve the surface quality of high-speed grinding. According to the mode shape graphs and the power spectra, the vibration weak links and the main vibration sources of the prototype were found, and then the improvement measures were presented by designing the dynamic performance tests. The fact that the chatter of high-speed grinding can be suppressed to a certain extent with variable speed grindings was verified in variable speed grinding experiments at high speed.

Analysis and Experimental Investigation of Chatter Suppression in High-Speed Cylindrical Grinding

2010 ◽  
Vol 34-35 ◽  
pp. 1936-1940 ◽  
Author(s):  
Xiao Long Shen ◽  
Lai Xi Zhang ◽  
Hua Long ◽  
Zhi Xiong Zhou
Keyword(s):  
Experimental Investigation ◽  
High Speed ◽  
Spectral Estimation ◽  
Vibration Energy ◽  
Variable Speed ◽  
Vibration Signals ◽  
Chatter Suppression ◽  
High Speed Grinding ◽  
The Stability

In this paper, the variable speed grinding experiments at high speed have been studied systematically, and the method of improving the surface quality of high-speed grinding has been discussed on the basis of analysis of the chatter and the stability of the high-speed grinder. Through the variable speed grinding experiments at high speed, the vibration characteristics were measured by the vibration energy, and the power spectrum were analyzed by the maximum entropy spectral estimation of the vibration signals in time series. The results confirm that the chatter of high-speed grinding can be suppressed by the variable speed grinding to a certain extent.

Research on Surface Quality for CBN Grinding Wheel Based on “Speed Effect”

2015 ◽  
Vol 667 ◽  
pp. 130-135
Author(s):  
Xue Sun ◽  
Tian Biao Yu ◽  
Wan Shan Wang
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
High Speed ◽  
Grinding Wheel ◽  
Grinding Speed ◽  
High Speed Grinding ◽  
Metal Materials ◽  
Speed Effect ◽  
Cbn Grinding Wheel

In order to study the influence of grinding surface quality affected by grinding speed for CBN grinding wheel, the method of simulation and experimentation used to study grinding surface quality of CBN grinding wheel. First, on the basis of grinding wheel topography, the influence of grinding surface quality affected by grinding speed was analyzed by adopting motion simulation method. Then, high-speed grinding experiment was carried out to three kinds of metal materials, and machined surface roughness and surface hardness after processing are measured and researched. Test shows that “speed effect” is remarkable in grinding metal materials. As the grinding speed increases, the grinding surface quality of workpiece is gradually improved. With the speed increasing, surface roughness of workpiecedecreases, and at lower speeds the surface roughness dropped more obvious. With grinding speed increases further, the change of roughness tends to be slow, and the bending point appears at about 100m/s.Surface hardening degree decreases with grinding speed increasing, when grinding speed up to high-speed grinding stage, the degree of hardening of the workpiece is more soothing.

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