Development of a New Plate Polishing Technique with an Instantaneous Tiny-Grinding Wheel Cluster Based on Magnetorheological Effect

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.

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.


2007 ◽  
Vol 359-360 ◽  
pp. 384-388
Author(s):  
Feng Jun Chen ◽  
Shao Hui Yin ◽  
Jian Wu Yu ◽  
Hitoshi Ohmori ◽  
Wei Min Lin ◽  
...  

According to the sharp rheological characteristics of magnetorheological fluid in the magnetic field, the principle and mechanism of magnetorheological finishing is analyzed. Based on the Preston equation, the Reynolds equation and its boundary conditions, the two-dimensional material removal model is built and simulated. Furthermore, a series of MRF experiments are carried out, and the influence of the immersed depth and material kinds on material removal rate are clarified respectively. The experimental results are compared with the modeling results of material removal rate to confirm the mechanistic model validity.


2006 ◽  
Vol 304-305 ◽  
pp. 555-559 ◽  
Author(s):  
Chang He Li ◽  
Guang Qi Cai ◽  
Shi Chao Xiu ◽  
Q. Li

The material removal rate (MRR) model was investigated in abrasive jet precision finishing (AJPF) with wheel as restraint. When abrasive wore and workpiece surface micro-protrusion removed, the size ratio for characteristic particle size to minimum film thickness gradually diminishing, the abrasive machining from two-body lapping to three-body polishing transition in AJPF with grinding wheel as restraint. In the study, the material removal rate model was established according to machining mechanisms and machining modes from two-body to three-body process transition condition, and active number of particles in grinding zone were calculated and simulated. Experiments were performed in the plane grinder for material removal mechanism and academic models verification. It can be observed from experimental results that the surface morphology change dramatically to a grooved or micro-machined surface with all the grooves aligned in the sliding direction in two-body lapping mode. On the other hand, the surface is very different, consists of a random machining pits with very little sign of any directionality to the deformation in the three-body machining mode. Furthermore, the material removal rate model was found to give a good description of the experimental results.


2006 ◽  
Vol 532-533 ◽  
pp. 145-148 ◽  
Author(s):  
Jia Bin Lu ◽  
Juan Yu ◽  
Qiu Sheng Yan ◽  
Wei Qiang Gao ◽  
Liang Chi Zhang

Based on the magnetorheological (MR) effect of abrasive slurry, this paper presents an innovative superfine machining method. In this technique, the particle-dispersed MR fluid is used as a special instantaneous bond to cohere abrasive particles and magnetic particles so as to form a dynamical tiny-grinding wheel. This tiny-grinding wheel can be used to polish the surface of brittle materials in millimeter or sub-millimeter scale. The characteristics of the machined glass surfaces examined by the scanning electron microscope (SEM) and the Talysurf roughness tester confirmed the effectiveness of the finishing technique. The machined surface with convex center and concave fringe demonstrates that the material removal process is dominated by the synergy of the applied pressure and the relative velocity between the abrasives and workpiece. In the case of glass finishing, the mode of material removal is found to be plastic, and controlled by the abrasive-wear mechanism.


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.


2008 ◽  
Vol 389-390 ◽  
pp. 187-192
Author(s):  
Yong Bo Wu ◽  
Kunio Shimada

This paper deals with the machining of quartz wafers using an MCF (Magnetic Compound Fluid) polishing liquid, frozen with liquid nitrogen. This type of polishing liquid is composed of water-based MF (Magnetic Fluid), iron powder, abrasive particle and α-cellulose, and consequently reacting to magnetic fields. Experiments of polishing quartz wafers using the MCF method were carried out on a previously developed apparatus. The results show that an MCF polishing liquid, frozen with liquid nitrogen, has greater material removal capability than one that has not been frozen. A frozen MCF polishing liquid containing larger abrasive particles yields a higher material removal rate, however the surface roughness deteriorates. The highest material removal rate and the best surface roughness were obtained when the percentage of water, in the frozen MCF polishing tool, was 34.7%.


2021 ◽  
Author(s):  
Yingdong Liang ◽  
Chao Zhang ◽  
Xin Chen ◽  
Tianqi Zhang ◽  
Tianbiao Yu ◽  
...  

Abstract The emergence of ultrasonic vibration-assisted polishing technology has effectively improved the machining accuracy and efficiency of hard and brittle materials in modern optical industry, however, the material removal mechanism of ultrasonic vibration-assisted polishing (UVAP) still needs to be further revealed. This paper focuses on the material removal mechanism of ultrasonic vibration-assisted polishing of optical glass (BK7), the application of ultrasonic vibration to axial vibration and the atomization of polishing slurry, the material removal model was established. Based on the analysis of the relationship between the nominal distance d of the polishing pad and the actual contact area distribution, the prediction of the material removal profile is realized. In addition, the effects of different parameters on the material removal rate (MRR) were analyzed, including polishing force, spindle speed, abrasive particle size, ultrasonic amplitude, feed rate, and flow-rate of polishing slurry. Based on the motion equation of abrasive particles, the trajectory of abrasive particles in the polishing slurry was simulated, and the simulation results show that the introduction of the ultrasonic vibration field changes the motion state and trajectory of embedded and free abrasive particles. The new model can not only qualitatively analyze the influence of different process parameters on MRR, but also predict the material removal depth and MRR, providing a possibility for deterministic material removal and a theoretical basis for subsequent polishing of complex curved surfaces of optical glass.


Author(s):  
Petr Hlavacek ◽  
Sergej Hloch ◽  
Akash Nag ◽  
Jana Petru ◽  
Miroslav Muller ◽  
...  

In this study, a new methodology is considered for determining the rotational senses (clockwise or anti-clockwise) of a workpiece during the hydroabrasive disintegration of rotating samples. The rotational directions are taken with respect to the position of the abrasive jet, that is, keeping it on the right side of the rotating workpiece when viewed from the free end in the cartesian coordinate system. Measurements were carried out for diameter deviation, material removal rate and surface roughness as a response to machining parameters such as traverse speed, workpiece rotation direction and abrasive grain. Final diameter of the workpiece (10.28–14.12 mm), material removal rate (1154–3936 mm3/min) and surface roughness (6.65–25.43 µm) values increase with increasing value of traverse speed (5–25 mm/min) using anti-clockwise rotation with Australian garnet abrasive grains. ANOVA analysis of the responses shows that traverse speed ( p = 0.000) is a statistically significant parameter for predicting all the machining responses. Abrasive type and rotational direction were statistically significant for determining diameter deviation ( p = 0.017, 0.006) and material removal rate ( p = 0.000, 0.000) but insignificant for surface roughness ( p = 0.373, 0.367). Scanning electron microscopy provided information on the surface morphology, depicting the characteristics of the disintegrated surface. Disintegrated features, like peak and valley formations, craters, holes, cutting traces and embedded abrasive particles on the surface were observed.


2007 ◽  
Vol 364-366 ◽  
pp. 914-919 ◽  
Author(s):  
Juan Yu ◽  
Qiu Sheng Yan ◽  
Jia Bin Lu ◽  
Wei Qiang Gao

Based on the magnetorheological (MR) effect of abrasive slurry, the particle-dispersed MR fluid is used as a special instantaneous bond to cohere abrasive particles and magnetic particles so as to form a dynamic, flexible tiny-grinding wheel to polish optical glass, ceramic and other brittle materials of millimeter or sub-millimeter scale with a high efficiency. Experiments were conducted to reveal the effects of different process parameters, such as grain sizes of abrasive particles, machining time, machining gap between the workpiece and the rotation tool, and rotation speed of the tool, on material removal rate of glass surface. The results indicate the following conclusions: material removal rate increases when the grain size of abrasives is similar to that of magnetic particles; machining time is directly proportional to material removal, but inversely proportional to material removal rate; machining gap is inversely proportional to material removal; polishing speed has both positive and negative influence on material removal rate, and greater material removal rate can be obtained at a certain rotation speed. In addition, the difference of the machining characteristics between this new method and the traditional fixed-abrasive machining method is analyzed.


2021 ◽  
Vol 11 (9) ◽  
pp. 3950
Author(s):  
Taekyung Lee ◽  
Haedo Jeong ◽  
Sangjik Lee ◽  
Hanchul Cho ◽  
Doyeon Kim ◽  
...  

The increasing demand for single-crystal wafers combined with the increase in diameter of semiconductor wafers has warranted further improvements in thickness variation and material removal rate during lapping to ensure price competitiveness of wafers; consequently, the lapping process has gained the attention of researchers. However, there is insufficient research on the effect of platen grooves on the lapping process. In this study, the parameters to describe grooves were defined in order to understand their influence on the lapping process, and a material removal model was suggested based on indentation theory and subsequently experimentally validated. The results indicate that changes in groove density affect the lubrication condition at the contact interface as well as the probability of abrasive participation by varying the oil film thickness. When fabricating the groove for a lapping platen, a groove density at the critical groove density (CGD) or higher should be selected. The higher the groove density, the easier it is to avoid the CGD, and the higher is the material removal rate. The results of this study will enable engineers to design lapping platen grooves that are suitable for the production of modern semiconductor wafers.


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