Ultra Smooth Planarization Polishing Technique Based on the Cluster Magnetorheological Effect

2010 ◽  
Vol 135 ◽  
pp. 18-23 ◽  
Author(s):  
Qiu Sheng Yan ◽  
Jie Wen Yan ◽  
Jia Bin Lu ◽  
Wei Qiang Gao

A new planarization polishing method based on the cluster magnetorheological (MR) effect is presented to polish optical glass in this paper. Some process experiments were conducted to reveal the influence of the content of carbonyl iron and the abrasive materials in the MR fluid on the machining effect, and the machining characteristic of polished surface was studied. The results indicate that the surface roughness of the polished workpiece can be reduced rapidly when the strong magnetic field is applied, and ultra smooth surface with Ra 1.4 nm can be achieved while the CeO2 abrasives are used in the MR fluid. The content of carbonyl iron obviously influences the machining effect of this planarization polishing method based on cluster MR-effect. With the increase of the content of carbonyl iron in the MR fluid, the material removal rate improves and the surface roughness reduces rapidly. However, the difference of abrasive material results in various machining effects. As for the K9 optical glass, the CeO2 abrasive is better polishing abrasive than the SiC abrasive in the planarization polishing technique based on the cluster MR-effect.

2011 ◽  
Vol 325 ◽  
pp. 542-547
Author(s):  
Qiu Sheng Yan ◽  
Jie Wen Yan ◽  
Jia Bin Lu ◽  
Wei Qiang Gao ◽  
Min Li

A new planarization grinding method based on the cluster magnetorheological (MR) effect is presented to grind optical glass in this paper. Some process experiments were conducted to reveal the influence of the species and granularity and content of the abrasive materials in the MR fluid on the machining effect, furthermore, the machining characteristic of grinded surface was studied. The results indicate that the abrasive influences definitively on machining effect of this planarization grinding method based on the cluster MR-effect. Under the certain experiment condition, with the content of the abrasive 10% and grain size 800# of SiC, best machining effect can be achieved. The difference species of abrasive results in various machining effects. As for the removal rate of K9 optical glass: abrasive CeO2 is the best, the Al2O3 is the second and the SiC is the worst. While the surface roughness: abrasive SiC is the lowest,the Al2O3 is the second and CeO2 is the highest.


2008 ◽  
Vol 53-54 ◽  
pp. 155-160 ◽  
Author(s):  
Qiu Sheng Yan ◽  
Ai Jun Tang ◽  
Jia Bin Lu ◽  
Wei Qiang Gao

A new plate polishing technique with an instantaneous tiny-grinding wheel cluster based on the magnetorheological (MR) effect is presented in this paper, and some experiments were conducted to prove its effectiveness and applicability. Under certain experimental condition, the material removal rate was improved by a factor of 20.84% as compared with the conventional polishing methods with dissociative abrasive particles, while the surface roughness of the workpiece was not obviously increased. Furthermore, the composite of the MR fluid was optimized to obtain the best polishing performance. On the basis of the experimental results, the material removal model of the new plate polishing technique was presented.


2010 ◽  
Vol 443 ◽  
pp. 406-410 ◽  
Author(s):  
Jie Wen Yan ◽  
Qiu Sheng Yan ◽  
Jia Bin Lu ◽  
Wei Qiang Gao

A new tiny-grinding wheel cluster polishing method based on the Magnetorheological (MR) effect is presented to polish optical glass in this paper and some process experiments were conducted to reveal the influence of magnetic field strength, the content of carbonyl iron in the MR fluid and the speed of polishing disc on the material removal rate and the surface roughness of the glass workpiece. The results indicate that when the external magnetic field is applied, the material removal rate of the workpiece improves rapidly but the surface roughness increases slightly. When the Magnetic field strength is 100 Gs and the content of carbonyl iron is 3.5%, the material removal rate improves by a factor of 16.8% compared with that of the conventional polishing methods with dissociative abrasive particles, while the surface roughness of the workpiece increases unobviously.


Author(s):  
H. Xu ◽  
K. Komvopoulos

A quasi-static mechanics analysis of nanoscale surface polishing that provides insight into the surface topography evolution and the removal of material at the asperity level is presented. The analysis is based on a three-dimensional stochastic model that accounts for multiscale (fractal) surface roughness and elastic, elastic-plastic, and fully plastic asperity deformation by hard abrasive nanoparticles embedded in the soft surface layer of a rigid polishing plate. Numerical results of the steady-state roughness of the polished surface, material removal rate, and wear coefficient are presented in terms of the apparent contact pressure, polishing speed, original topography and mechanical properties of the polished surface, average size and density of nanoparticles, and surface roughness of the polishing plate. Simulation trends are associated with elastic-plastic and fully plastic asperity contacts, responsible for irreversible topography changes (roughening effect) and material removal (smoothening effect), respectively. Analytical trends and predictions of the steady-state roughness of the polished surface and material removal rate are shown to be in good agreement with experimental results of nanoscale surface polishing (lapping) of magnetic recording ceramic heads.


2012 ◽  
Vol 523-524 ◽  
pp. 155-160 ◽  
Author(s):  
Ya Guo Li ◽  
Yong Bo Wu ◽  
Li Bo Zhou ◽  
Hui Ru Guo ◽  
Jian Guo Cao ◽  
...  

Ultrasonic vibration assisted processing is well known for the improvement in machined surface quality and processing efficiency due to the reduced forces and tribology-generated heating when grinding hard-brittle materials. We transplanted this philosophy to chemo-mechanical fixed abrasive polishing of optical glass, namely fused silica, in an attempt to improve surface roughness and/or material removal rate. Experiments were conducted to elucidate the fundamental characteristics of chemo-mechanical fixed abrasive polishing of fused silica in the presence and absence of ultrasonic vibration on a setup with an in-house built gadget. The experimental results show that ultrasonic vibration assisted chemo-mechanical fixed abrasive polishing can yield increased material removal rate while maintaining the surface roughness of manufactured optics compared to conventional fixed abrasive polishing without ultrasonic vibration. The mechanism of material removal in fixed abrasive polishing was also delved. We found that the glass material is removed through the synergic effects of chemical and mechanical actions between abrasives and glass and the resultant grinding swarf contains ample Si element as well as Ce element, standing in stark contrast to the polisher that contains abundant Ce element and minor Si element.


2012 ◽  
Vol 516 ◽  
pp. 79-83
Author(s):  
Jie Wen Yan ◽  
Qiu Sheng Yan ◽  
Jia Bin Lu ◽  
Wei Qiang Gao ◽  
Zhi Ying Huang

A new planarization polishing method, based on the cluster magnetorheological (MR) effect and using MR fluid to form the flexible polishing pad, is presented in this paper to polish optical glass. To explore the machining characteristic of the viscid and flexible polishing pad based on the cluster MR-effect, some process experiments were conducted to reveal the influence of the machining gap, the speed of the polishing disc and the polishing time on the machining effect. The results indicate that the viscid and flexible polishing pad based on the cluster MR-effect under a strong magnetic field can reduce surface roughness effectively. When the strength of the magnetic field is 2000Gs, and the content of the carbonyl iron is 12%, the surface roughness can be reduced rapidly from the original Ra0.27μm to Ra1.4nm based on the cluster MR-effect.


2009 ◽  
Vol 76-78 ◽  
pp. 229-234 ◽  
Author(s):  
Qiu Sheng Yan ◽  
Yong Yang ◽  
Jia Bin Lu ◽  
Wei Qiang Gao

Experiments were conducted to polish optical glass with the magnetorheological (MR) effect-based tiny-grinding wheel cluster, and the influences of abrasive material, particle size and content on the material removal rate and surface roughness are investigated. The experimental results indicate that: the higher the hardness of abrasives, the higher the material removal rate, but the abrasives with lower hardness can obtain lower surface roughness. The better polishing quality of the workpiece can be obtained when the particle size of abrasives is similar to the particle size of magnetic particles. Moreover, the content of abrasives has an optimum value, and the material removal rate and the surface quality can not be improved further when the content of abrasives exceeds the optimum value. On the basis of above, the material removal model of the new planarization polishing technique is presented.


2011 ◽  
Vol 487 ◽  
pp. 283-288 ◽  
Author(s):  
Zhan Cheng Wu ◽  
Qiu Sheng Yan ◽  
Zhen Wei Bai ◽  
Ling Ye Kong ◽  
Jing Fu Chai

Based on the principle of MR polishing processing, cluster MR-effect polishing method which formed by cluster distributed magnetic body has been put forward in this article. The author analyzed the principle of the cluster MR-effect plane polishing, developed experimental device and conducted processing experiment to K9 optical glass and silicon slice. Results show that the method is feasible and can realize high precision polishing. The surface roughness of K9 glass and silicon slice can achieve respectively Ra0.005µm and Ra0.016µm finally after processed. It has high efficiency at the same time, the surface roughness can decrease 1 order of magnitude after processed 10 minutes, the surface roughness of K9 glass and silicon slice can realize respectively decrease 3 orders of magnitude and 1 order of magnitude after processed 50 minutes.


2011 ◽  
Vol 487 ◽  
pp. 257-262 ◽  
Author(s):  
Cheng Yong Wang ◽  
Wu Sheng Luo ◽  
C.H. He ◽  
Yue Xian Song

BK7 optical glass is used as the object of study in this paper. The different parameters such as lapping time, load, slurry flow, slurry concentration, abrasive grain sizes, rotating speed effect on surface roughness and material removal volume are studied. Using the way of orthogonal experiments for seeking optimization parameters to gain the smoothness surface and consume the minimum machining time. The empirical formulas of surface roughness and material removal rate are found by orthogonal test.


2014 ◽  
Vol 1002 ◽  
pp. 57-60
Author(s):  
Heng Zhen Dai ◽  
Zhen Hua Jiao ◽  
Bin Wang ◽  
Zhu Ji Jin

K9 optical glass was widely used in national defense and civilian fields. In this paper, chemo-mechanical grinding (CMG) was applied to process the K9 optical glass. Selecting CeO2, MgO and Fe2O3as CMG abrasives, the corresponding CMG tools were purposely developed for the check experiment. High surface and subsurface qualities on the K9 optical glass specimen were obtained as the polished results by the CeO2-CMG tools. Surface roughness and material removal rate were used to evaluate the grinding performance. The low-abrasive ratio of CeO2-CMG tool was proved as the optimal one, by which the surface roughness Ra reached 0.586nm, and the surface morphology appeared smooth and flat. The angle polishing was applied to detect the subsurface quality and the subsurface cracks were not observed.


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