Analysis on the Effects of Grinding Wheel Speed on Removal Behavior of Brittle Optical Materials

Author(s):  
Ping Li ◽  
Tan Jin ◽  
Zongfu Guo ◽  
Jun Yi ◽  
Meina Qu

It is often desired to increase the machining rate while maintaining the desired surface and subsurface integrity during fabricating high-quality optical glass components. This paper proposed a high-speed high-efficiency low-damage grinding technology for machining brittle optical materials, which consists of three grinding processes: rough grinding, semifinishing grinding, and finishing grinding. Grinding characteristics are investigated with respect to grinding forces, specific cutting energy, surface roughness, ground surface quality, subsurface damage, and material removal mechanisms in grinding of fused silica optical glasses with this technology at grinding speeds of up to 150 m/s. These indications are thoroughly discussed by contacting the undeformed chip thickness. The results indicate that the level of these indications is significantly improved with an increase in the wheel speed due to the decrease of the undeformed chip thickness. It is also found that the improvement of ground surface quality is limited when the wheel speed increases from 120 m/s to 150 m/s, which may be due to the influence of vibration caused by the higher wheel speed. For different grinding processes, these results are also substantially improved with the change of grinding conditions. It is found that the material removal mechanism is dominated by brittle fracture at rough and semifinishing grinding processes, while ductile flow mode can be observed at the finishing grinding process. There are some differences between the experimental results and the previous predicted model of subsurface damage depth.

2016 ◽  
Author(s):  
Ping Li ◽  
Tan Jin ◽  
Zongfu Guo ◽  
Jun Yi ◽  
Meina Qu

It is often desired to increase the machining rate while maintaining the desired surface and subsurface integrity during fabricating high-quality optical glass components. This paper proposed a high-speed high-efficiency low-damage grinding technology for machining brittle optical materials, which consists of three grinding processes: rough grinding, semi-finishing grinding and finishing grinding. Grinding characteristics is investigated with respect to grinding forces, specific cutting energy, surface roughness, ground surface quality, subsurface damage, and material removal mechanisms in grinding of fused silica optical glasses with this technology at the grinding speeds of up to 150 m/s. These indications are thoroughly discussed by contacting the undeformed chip thickness. The results indicate that the level of these indications are significantly improved with an increase in the wheel speed due to the decrease of the undeformed chip thickness. It is also found that the improvement of ground surface quality is limited when the wheel speed from 120 m/s increases to 150 m/s may be due to the influence of vibration caused by the higher wheel speed. For different grinding processes, these results are also substantially improved with the change of grinding conditions. It is found that the material removal mechanism is dominated by brittle fracture at rough and semi-finishing grinding processes, while ductile flow mode can be observed at the finishing grinding process. There are some differences between the experimental results and the previous predicted model of subsurface damage depth.


2021 ◽  
Author(s):  
Yonghao Wang ◽  
Ping Zhou ◽  
Yuhang Pan ◽  
Ying Yan ◽  
Dongming Guo

Abstract Grinding is a popular method for producing high-quality parts made of hard and brittle materials. A lot of researchers have focused on the impact of grinding parameters on surface quality. However, only a few studies discussed the surface quality instability caused by the grinding wheel wear during a long grinding process. In this paper, through wheel state monitoring and surface quality testing of ground samples, it is found that the relationship between ground surface roughness and theoretical undeformed chip thickness is significantly affected by the grinding wheel wear state, rather than maintain steady as described in most available models. By introducing the normal grinding force, a linearly relationship was found among normal grinding force, undeformed chip thickness and ground surface roughness. Besides, sensitivity analysis was conducted to guide the parameter adjustment to maintain the stability of ground surface roughness and grinding state. The mechanism of the effect of wheel wear on normal grinding force was also studied in detail. This study will help to further understand the mechanism of the influence of wheel wear on the grinding stability.


2010 ◽  
Vol 431-432 ◽  
pp. 326-329
Author(s):  
Shu Sheng Li ◽  
Jiu Hua Xu ◽  
Yu Can Fu ◽  
Hong Hua Su

A new brazed monolayer diamond grinding wheel is developed with the same continuous cutting edge distance on the wheel surface. Surface/subsurface damage of yttria partially stabilized zirconia (Y-PSZ) in grinding using monolayer brazed diamond wheel is analyzed. In this investigation, the influence of the maximum undeformed chip thickness (hm) on material removal mechanism is analyzed. The experiment results show that the ground surface is almost in ductile material removal mode when hm is below the critical value for Y-PSZ, otherwise it will be the combined removal modes of brittle and ductile when hm is above the critical value.


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.


2010 ◽  
Vol 431-432 ◽  
pp. 322-325
Author(s):  
Bei Zhang ◽  
Hong Hua Su ◽  
Hong Jun Xu ◽  
Yu Can Fu

Li-Ti ferrite used in aviation occasions needs good surface quality. In conventional grinding it is difficult to meet the surface demand. Accordingly, this paper proposed a new grinding process to change the situation. The process employed graphite grinding wheel which is always used in ultra-precision grinding of steel piece. The process can obtain good surface quality and ensure certain material removal rate. The ground surface appearance is nearly mirror-like. The lowest surface roughness of Ra value of the ground surface is 0.05μm in the experiment. The ground surface morphology is made up of spread glazed area and dispersed minute pits. The ductile regime dominates the material removal mechanism and no surface damage is induced in the process. In consideration of the results in the experiment it can be seen that grinding with graphite grinding wheel is a good finishing procedure in ferrite machining because of its obtained high surface quality.


2006 ◽  
Vol 304-305 ◽  
pp. 276-280 ◽  
Author(s):  
Y.H. Ren ◽  
Zhi Xiong Zhou ◽  
Zhao Hui Deng

Surface microgrinding of the nanostructured WC/12Co coatings have been undertaken with diamond wheels under various conditions. Nondestructive and destructive approaches were utilized to assess damage in ground nanostructured coatings. Different surface and subsurface configurations were observed by scanning electron microscopy. This paper investigates the effects of microgrinding conditions on damage formation in the surface and subsurface layers of the ground nanostructured WC/12Co coatings. And the material-removal mechanism has been discussed.


2007 ◽  
Vol 24-25 ◽  
pp. 229-232
Author(s):  
S.L. Ma ◽  
Wei Li ◽  
Cong Rong Zhu ◽  
J. Zhang ◽  
H.C. Ye

Tungsten carbide which is a hard and brittle material was ground by cast-iron bonded diamond wheel with ELID (Electrolytic In-Process Dressing) technique, for the purpose of getting high efficiency, super-precision machining. Three kinds of cast-iron bonded diamond wheels with different grain size were adopted to get different grinding efficiency and surface quality of workpieces. The grinding properties of cast-iron bonded grinding wheels with different grain size and the ground surface quality of tungsten carbide are discussed in this paper. The experiment results indicate that, under the same feeding amount, the grinding efficiency of the wheel with bigger grain size is higher, and it could make the dimension accuracy of the workpiece controllable, but the wheel with smaller grain size could get better ground surface quality. The two grinding phases are decided by the ratio between the size of abrasive grain and the thickness of the oxide layer on the grinding wheel.


2013 ◽  
Vol 457-458 ◽  
pp. 172-176
Author(s):  
Zong Fu Guo ◽  
Xiao Min Sheng ◽  
Gui Zhi Xie ◽  
De Zhen Yin ◽  
Wen Xin Li

This paper via investigate the process of 9SiCr alloy steel in high efficiency deep grinding to find the rule between grinding wheel speed vs depth of cut ap and speed of table vw with the grinding force and the surface quality. Intend to develop a suitable method of the grinding process of 9SiCr alloy steel in high efficiency deep grinding, to obtain high removal rate and good surface quality.


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