Effects of pressure and shear stress on material removal rate in ultra-fine polishing of optical glass with magnetic compound fluid slurry

2014 ◽  
Vol 214 (11) ◽  
pp. 2759-2769 ◽  
Author(s):  
Huiru Guo ◽  
Yongbo Wu ◽  
Dong Lu ◽  
Masakazu Fujimoto ◽  
Mitsuyoshi Nomura
Keyword(s):  
Shear Stress ◽  
Material Removal Rate ◽  
Material Removal ◽  
Optical Glass ◽  
Removal Rate

Parametric Study of Micro Machining Three Dimensional Microstructure with the Tiny-Grinding Wheel Based on the EMR Effect

2010 ◽  
Vol 447-448 ◽  
pp. 193-197
Author(s):  
Wei Qiang Gao ◽  
Qiu Sheng Yan ◽  
Yi Liu ◽  
Jia Bin Lu ◽  
Ling Ye Kong
Keyword(s):  
Magnetic Field ◽  
Material Removal Rate ◽  
Feed Rate ◽  
Material Removal ◽  
Rotation Speed ◽  
Optical Glass ◽  
Removal Rate ◽  
Grinding Wheel ◽  
Machining Time ◽  
Fluctuation Phenomenon

Electro-magneto-rheological (EMR) fluids, which exhibit Newtonian behavior in the absence of a magnetic field, are abruptly transformed within milliseconds into a Bingham plastic under an applied magnetic field, called the EMR effect. Based on this effect, the particle-dispersed EMR fluid is used as a special instantaneous bond to cohere abrasive particles and magnetic particles together so as to form a dynamical, flexible tiny-grinding wheel to machine micro-groove on the surface of optical glass. Experiments were conducted to reveal the effects of process parameters, such as the feed rate of the horizontal worktable, feeding of the Z axis, machining time and machining gap, on material removal rate of glass. The results indicate that the feed rate of the worktable at horizontal direction has less effect on material removal rate, which shows a fluctuation phenomenon within a certain range. The feed rate of the Z axis directly influences the machining gap and leads to a remarkable change on material removal rate. Larger material removal rate can be obtained when the feeding frequency of Z direction is one time per processing. With the increase of rotation speed of the tool, material removal rate increases firstly and decreases afterwards, and it gets the maximum value with the rotation speed of 4800 rev/min. The machining time is directly proportional to material removal amount, but inversely proportional to material removal rate. Furthermore, material removal rate decreases with the increase of the machining gap between the tool and the workpiece. On the basis of above, the machining mode with the tiny-grinding wheel based on the EMR effect is presented.

Investigation into Chemo-Mechanical Fixed Abrasive Polishing of Fused Silica with the Assistance of Ultrasonic Vibration

2012 ◽  
Vol 523-524 ◽  
pp. 155-160 ◽  
Author(s):  
Ya Guo Li ◽  
Yong Bo Wu ◽  
Li Bo Zhou ◽  
Hui Ru Guo ◽  
Jian Guo Cao ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Ultrasonic Vibration ◽  
Material Removal Rate ◽  
Material Removal ◽  
Optical Glass ◽  
Removal Rate ◽  
Fused Silica ◽  
Processing Efficiency ◽  
Machined Surface ◽  
Fixed Abrasive

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.

scholarly journals Theoretical Modeling and Experimental Analysis of Single-Particle Erosion Mechanism of Optical Glass

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1221
Author(s):  
Zhongchen Cao ◽  
Shengqin Yan ◽  
Shipeng Li ◽  
Yang Zhang
Keyword(s):  
Particle Size ◽  
Impact Velocity ◽  
Material Removal Rate ◽  
Single Particle ◽  
Material Removal ◽  
Optical Glass ◽  
Removal Rate ◽  
Impact Angle ◽  
Particle Erosion ◽  
Erosion Mechanism

The study of the single-particle erosion mechanism is essential to understand the material removal mechanism in the non-contact polishing process and ultimately ensure the high-efficiency, non-damage, and ultra-smooth processing of optical glass. In this study, the theoretical model of smoothed particle hydrodynamics (SPH) is established to reveal the dynamic removal process of a single particle impacting the optical glass. The single-particle erosion mechanisms, which include ductile–brittle transition, crack initiation, and propagation, are discussed in detail through theoretical simulation. A series of particle impact experiments are designed to validate the correctness of the SPH model. The experimental data show good agreement with the simulation results in terms of the depth and width of the eroded craters. Thereafter, the SPH simulation is conducted by studying the effect of various impact parameters, such as impact speed, impact angle, and abrasive diameter, on the material removal process. With the gradual increase of impact velocity and particle size, the material removal mode changes from plastic removal to brittle removal. Although the large impact velocity and particle size increase the material removal rate, they lead to the occurrence of brittle removal and reduce the surface and sub-surface quality. When the impact angle is between 45° and 75°, the material removal rate is the largest, and the increase of the material removal rate does not cause damage to the subsurface layer of the material.

scholarly journals Modeling and Analysis of the Material Removal Rate for Ultrasonic Vibration-assisted Polishing of Optical Glass BK7

2021 ◽  
Author(s):  
Yingdong Liang ◽  
Chao Zhang ◽  
Xin Chen ◽  
Tianqi Zhang ◽  
Tianbiao Yu ◽  
...  
Keyword(s):  
Ultrasonic Vibration ◽  
Material Removal Rate ◽  
Material Removal ◽  
Optical Glass ◽  
Removal Rate ◽  
Machining Accuracy ◽  
Removal Mechanism ◽  
Material Removal Mechanism ◽  
Abrasive Particles ◽  
Material Removal Model

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.

Influence of Abrasive on Planarization Polishing with the Tiny-Grinding Wheel Cluster Based on the Magnetorheological Effect

2009 ◽  
Vol 76-78 ◽  
pp. 229-234 ◽  
Author(s):  
Qiu Sheng Yan ◽  
Yong Yang ◽  
Jia Bin Lu ◽  
Wei Qiang Gao
Keyword(s):  
Surface Roughness ◽  
Particle Size ◽  
Material Removal Rate ◽  
Material Removal ◽  
Magnetic Particles ◽  
Optical Glass ◽  
Removal Rate ◽  
Grinding Wheel ◽  
Material Particle ◽  
Material Removal Model

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.

Research on Material Removal of a New Micro Machining Technology Based on the Magnetorheological Effect of Abrasive Slurry

2007 ◽  
Vol 364-366 ◽  
pp. 914-919 ◽  
Author(s):  
Juan Yu ◽  
Qiu Sheng Yan ◽  
Jia Bin Lu ◽  
Wei Qiang Gao
Keyword(s):  
Material Removal Rate ◽  
Material Removal ◽  
Magnetic Particles ◽  
High Efficiency ◽  
Rotation Speed ◽  
Optical Glass ◽  
Removal Rate ◽  
Grinding Wheel ◽  
Machining Time ◽  
Abrasive Particles

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.

Bonds of Electroplated Diamond Tools for Optical Glass Machining

2006 ◽  
Vol 304-305 ◽  
pp. 81-84
Author(s):  
Ai Bing Yu ◽  
A.J. Wang ◽  
C.G. Luan ◽  
S.F. Chen
Keyword(s):  
Heat Treatment ◽  
Material Removal Rate ◽  
Material Removal ◽  
Diamond Tool ◽  
Optical Glass ◽  
Removal Rate ◽  
Diamond Tools ◽  
Treatment Processes ◽  
Nickel Cobalt ◽  
Grinding Ratio

Bonds of electroplated diamond tools are investigated through the studies of microstructures and properties. Three coatings for tool bonds, nickel, nickel-cobalt and bright nickel, were fabricated with electrodeposition processes, and were heat-treated with different temperatures. The hardness and microstructures of coatings were measured and observed. Optical glass K9 was machined with fabricated electroplated diamond tools to compare material removal rate and grinding ratio. The grain sizes of three bond coatings are different. The laminar structures of nickel-cobalt and bright nickel coatings turn to fine columnar structure after heat treatment processes. With heat treatment of 200°C temperature, bright nickel electroplated diamond tool presents highest values of material removal rate and grinding ratio. The research results show that better microstructures and property of bond for electroplated diamond tool can be obtained by selecting proper electroplating technology and heat treatment processes.

Influence of Magnetic Field Strength on Polishing Effect of the Tiny-Grinding Wheel Cluster Based on the Magnetorheological Effect

2010 ◽  
Vol 443 ◽  
pp. 406-410 ◽  
Author(s):  
Jie Wen Yan ◽  
Qiu Sheng Yan ◽  
Jia Bin Lu ◽  
Wei Qiang Gao
Keyword(s):  
Magnetic Field ◽  
Surface Roughness ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Material Removal Rate ◽  
Carbonyl Iron ◽  
Material Removal ◽  
Optical Glass ◽  
Removal Rate ◽  
Grinding Wheel

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.

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