Super-Smooth Grinding Behavior of SiC Ceramics by the Use of Coarse Diamond Grinding Wheel

Author(s):  
J. Xie ◽  
S. W. Wang

A new super-smooth grinding method for SiC ceramics was proposed by the use of coarse diamond grinding wheel. It can enhance ultra-precision grinding efficiency in comparison with ELID (electrolytic in-process dressing) mirror grinding with super-fine diamond grinding wheel. In grinding, wheel moving direction is vertical to cutting direction different from traditional plunge and traverse grinding and dressing + iron-truing was also employed to protrude and truncate grit cutting edges, improving grit protrusion feature. First, formation of super-smooth ground surface was theoretically analyzed on the base of grit cutting depth and surface roughness. Next, theoretical effect of grinding parameters and grit protrusion parameters on grit cutting depth and surface roughness was discussed. Then, orthogonal experiments were conducted to investigate effect of grinding parameters on surface roughness. Finally, dressing experiment and iron-truing experiment were carried out respectively to investigate ductile-mode mirror grinding behavior in connection with wheel moving speed and grit protrusion feature. Theoretical analysis showed that grit cutting depth and surface roughness depend on wheel rotating speed, wheel moving speed, grit cutting edge number and grit cutting edge angle, but they were not dominated by the depth of cut. Experimental results showed that a super-smooth ground surface can be obtained by decreasing wheel moving speed and improving grit protrusion feature. In addition, the ductile mode grinding may be conducted to realize mirror grinding of SiC ceramics by using wheel moving speed of 5 mm/min and dressing + iron-truing conditions before grinding.

2013 ◽  
Vol 797 ◽  
pp. 234-239 ◽  
Author(s):  
Li Fei Liu ◽  
Fei Hu Zhang ◽  
Chun Hui Li ◽  
Jiang Chen ◽  
Min Hui Liu

In this paper, experiments are conducted to study the characters of Ultrasonic Assisted Grinding (UAG) and Conventional Grinding (CG), diamond grinding wheel is used in experiments, grinding forces and surface roughness are measured in both UAG and CG. The effects of different parameters on grinding force, surface roughness and force ratio are discussed. The results show that the grinding force and surface roughness in UAG is smaller than those in CG. The force ratio in UAG is lower than that in CG, which reveals that the grinding wheel has a good wear-resistant property in UAG process.


2014 ◽  
Vol 1027 ◽  
pp. 159-162 ◽  
Author(s):  
Kun Zhang ◽  
Hong Hua Su ◽  
Feng Ming Dai

A monolayer brazed diamond grinding wheel was dressed 23 times with a plate wheel. The grinding forces were measured during the grinding experiments which carried out on SiC ceramics after each dressing interval. The surface roughness of SiC ceramics was also measured. In this study, the dullness of the grinding wheel during the dressing procedure is mainly discussed. The results showed that the surface roughness of SiC ceramics reduced a lot after dressing which means the dressed grinding wheel can meet the requirements of precision machining. On the premise of this, there was no obvious dullness occurred on the grits of the grinding wheel during dressing because new cutting edges had emerged.


Author(s):  
Chen Li ◽  
Feihu Zhang ◽  
Zhaokai Ma

In order to explore the grinding surface deformation and subsurface damage mechanism for reaction-bonded SiC ceramics, the grinding experiment for reaction-bonded SiC ceramics was carried out under the condition of different grinding depths using two different kinds of grain sizes of grinding wheel. The ground surface morphology of specimen was observed using the field emission scanning electron microscope (5000 ×), and the value of surface roughness Rz was measured by the confocal microscope, which found that there were the brittle removal region and the plastic removal region on the ground surface of reaction-bonded SiC ceramics and it could improve the ground surface quality and proportion of ductile region using the fine grinding wheel and reducing the grinding depth. The specimen was polished by the ion cross section polisher and the ground subsurface was analyzed by the field emission scanning electron microscope, which found that there were transgranular fracture, intergranular fracture, crack bifurcation, ladder-shaped crack and other phenomenon in the grinding process. And it could control the subsurface damage depth using the fine grinding wheel and reducing the grinding depth. The relationship between surface roughness and subsurface damage was analyzed based on the indentation theory, which found that the simulation results were close to the experiment results when the value of m is in the range of 1/8–1/4. When m is 0.2143 calculated by genetic algorithm, the simulation results are the best.


2006 ◽  
Vol 304-305 ◽  
pp. 76-80 ◽  
Author(s):  
Jin Xie ◽  
Yong Tang ◽  
Junichi Tamaki

This paper conducted Electro-Contact Discharge (ECD) dressing experiment for #600 diamond grinding wheel to understand how fine diamond grits protrude from metal-bonded wheel surface. The SEM observation, EDS analysis, image processing and 3D grit modeling on wheel surface were carried out to investigate grit protrusion characteristics. Then ECD dressing and mechanical dressing experiments were carried out to identify the effect of grit protrusion feature on grinding performance. It is confirmed that the dressed wheel surface topography is sensitive to open circuit voltage Ei, discharge polarity and electrode composition. Meanwhile, ECD dressing with Ei=15V and straight polarity can produce superior protrusion topography without the damage of diamond crystal faces and the bond tail behind protrusive grit. It can obtain better ground surface of hard-brittle material than mechanical dressing with the bond tail.


2011 ◽  
Vol 299-300 ◽  
pp. 1060-1063 ◽  
Author(s):  
Y.X. Yao ◽  
Jin Guang Du ◽  
Jian Guang Li ◽  
H. Zhao

Mill-grinding experiments were carried out on SiCp/Al to investigate effects of mill-grinding parameters and grinding wheel parameters on machined surface roughness in this paper. The machined surface topography was also analyzed. Experimental results show that surface roughness increases with increasing feed rate and the depth of the mill-grinding. The effect of mill-grinding speed on surface roughness is low. The machined surface reveals many defects. The fine grit diamond grinding wheel can reduce the surface roughness and decrease the machined surface defect. Compared to the vitrified bonded diamond and electroplated diamond grinding wheels used in the experiment, the resin-based diamond grinding wheel produces a better surface.


2017 ◽  
Vol 872 ◽  
pp. 19-24
Author(s):  
Zong Chao Geng ◽  
Shang Gao ◽  
Ren Ke Kang ◽  
Zhi Gang Dong

Quartz glass is a typical hard and brittle material. During the manufacturing process of quartz glass components, ultra-precision grinding is widely used due to its high throughput and good dimensional accuracies. However, grinding will unavoidably induce large surface and subsurface damage. In this study, the surface and subsurface damage characteristics of quartz glass substrates ground by diamond wheels with different grit sizes were investigated in terms of surface roughness, surface topography, subsurface microcrack characteristic, and subsurface damage depth. Discussion was also provided to explore corresponding reasons of surface and subsurface damage induced by diamond grinding wheels with different grit sizes of #1500 and #2000. The experiment results showed that the surface roughness, surface damage, and subsurface damage depth induced by #2000 quartz glass was ground by #1500 diamond grinding wheel, and in ductile mode when ground by #2000 diamond grinding wheel.


Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 625 ◽  
Author(s):  
Yanjun Lu ◽  
Wang Luo ◽  
Xiaoyu Wu ◽  
Chaolan Zhou ◽  
Bin Xu ◽  
...  

In this paper, in view of low grinding efficiency and poor ground surface quality of sapphire glass, the coarse diamond grinding wheel dressed by dry impulse electrical discharge was proposed to perform efficient and precise grinding machining of sapphire glass. The dry electrical discharge dressing technology was employed to obtain high grain protrusion and sharp micro-grain cutting edges. The influences of grinding process parameters such as wheel speed, depth of cut and feed speed on the ground surface quality, grinding force and grinding force ratio on sapphire glass were investigated, and the relationship between grinding force and ground surface quality was also revealed. The experimental results show that the grain protrusion height on the surface of a coarse diamond grinding wheel dressed by dry electrical discharge can reach 168.5 µm. The minimum line roughness Ra and surface roughness Sa of ground sapphire glass surface were 0.194 µm and 0.736 µm, respectively. In order to achieve highly efficient ground quality of sapphire glass, the depth of cut was controlled within 7 µm, and the wheel speed and feed speed were 3000–5000 r/min and 10–20 mm/min, respectively. The influences of feed speed and wheel speed on grinding force ratio were more significant, but the influence of depth of cut was little.


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