Theoretical model of brittle material removal fraction related to surface roughness and subsurface damage depth of optical glass during precision grinding

2017 ◽  
Vol 49 ◽  
pp. 421-427 ◽  
Author(s):  
Chen Jiang ◽  
Jinyi Cheng ◽  
Tao Wu
Keyword(s):  
Surface Roughness ◽  
Theoretical Model ◽  
Brittle Material ◽  
Material Removal ◽  
Optical Glass ◽  
Subsurface Damage ◽  
Precision Grinding ◽  
Damage Depth ◽  
Brittle Material Removal ◽  
Removal Fraction

Surface Layer Damage of Quartz Glass Induced by Ultra-Precision Grinding with Different Grit Size

2017 ◽  
Vol 872 ◽  
pp. 19-24
Author(s):  
Zong Chao Geng ◽  
Shang Gao ◽  
Ren Ke Kang ◽  
Zhi Gang Dong
Keyword(s):  
Surface Roughness ◽  
Quartz Glass ◽  
Subsurface Damage ◽  
Grinding Wheel ◽  
Precision Grinding ◽  
Diamond Grinding Wheel ◽  
Diamond Grinding ◽  
Roughness Surface ◽  
Ultra Precision ◽  
Damage Depth

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.

scholarly journals Experimental Study on Surface Integrity and Subsurface Damage of Fused Silica in Ultra-Precision Grinding

2021 ◽  
Author(s):  
Yaoyu Zhong ◽  
Yifan Dai ◽  
Hang Xiao ◽  
Feng Shi
Keyword(s):  
Surface Roughness ◽  
Plastic Flow ◽  
Material Removal ◽  
Cutting Speed ◽  
Fused Silica ◽  
Subsurface Damage ◽  
Depth Of Cut ◽  
Grinding Wheel ◽  
Precision Grinding ◽  
Ultra Precision

Abstract To realize low-damage ultra-precision grinding on fused silica, the surface quality and subsurface damage (SSD) distribution with fine-grained grinding wheel under different depth-of-cut and cutting speed are experimentally studied. The material removal mechanism under different grinding parameters is revealed by calculating undeformed chip thickness and observed with the help of transmission electron microscopy. The results show that brittle-ductile surfaces and ductile-like surfaces are generated during grinding. With the decrease of depth-of-cut and the increase of wheel cutting speed, the ultra-precision grinding changes to ductile-regime grinding with plastic flow removal. Besides, the surface roughness (SR) and SSD depth are reduced. The fracture defects such as fractured pits and grinding streaks on brittle-ductile surface gradually decrease. Instead, a ductile-like surface covered with grinding streaks is found. On brittle-ductile surfaces, the nonlinear relationship SSD∝SR4/3 is no longer proper under the influence of plastic flow. Using surface roughness Ra to predict SSD depth is more accurate. When depth-of-cut is 1 µm, cutting speed is 23.4 m/s and the material removal mode is dominated by plastic flow removal, the surface Ra is improved to 2.0 nm and there is no crack but only a 3.4 nm deep plastic flow layer in subsurface after grinding.

scholarly journals Simulation of the ductile machining mode of silicon

2021 ◽  
Author(s):  
Hagen Klippel ◽  
Stefan Süssmaier ◽  
Matthias Röthlin ◽  
Mohamadreza Afrasiabi ◽  
Uygar Pala ◽  
...  
Keyword(s):  
Brittle Material ◽  
Material Removal ◽  
Machining Process ◽  
Ductile Material ◽  
Diamond Wire ◽  
Ductile Machining ◽  
Mesh Free ◽  
Diamond Wire Sawing ◽  
Material Removal Mode ◽  
Brittle Material Removal

AbstractDiamond wire sawing has been developed to reduce the cutting loss when cutting silicon wafers from ingots. The surface of silicon solar cells must be flawless in order to achieve the highest possible efficiency. However, the surface is damaged during sawing. The extent of the damage depends primarily on the material removal mode. Under certain conditions, the generally brittle material can be machined in ductile mode, whereby considerably fewer cracks occur in the surface than with brittle material removal. In the presented paper, a numerical model is developed in order to support the optimisation of the machining process regarding the transition between ductile and brittle material removal. The simulations are performed with an GPU-accelerated in-house developed code using mesh-free methods which easily handle large deformations while classic methods like FEM would require intensive remeshing. The Johnson-Cook flow stress model is implemented and used to evaluate the applicability of a model for ductile material behaviour in the transition zone between ductile and brittle removal mode. The simulation results are compared with results obtained from single grain scratch experiments using a real, non-idealised grain geometry as present in the diamond wire sawing process.

scholarly journals Effect of Stress Wave between Adjacent Asperities Interaction on Subsurface Damage of Optical Glass in Precision Grinding

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1239
Author(s):  
Chen ◽  
Ren ◽  
Lin
Keyword(s):  
Finite Element ◽  
Optical Glass ◽  
Diamond Particle ◽  
Subsurface Damage ◽  
Propagation Mechanism ◽  
Analysis Model ◽  
Precision Grinding ◽  
Element Analysis ◽  
Analysis Process ◽  
Element Simulation

The interaction between adjacent asperities is a typical characteristic of the grinding process and plays an important role in the material removal mechanism. Therefore, in order to systematically investigate the formation mechanism of the subsurface damage, a precision grinding contact model between the diamond particle and optical glass with adjacent asperities is proposed in our research. The initiation and propagation mechanism of median/lateral cracks under residual stress, the propagation rules of the stress waves on the subsurface, and the interaction between the subsurface damage under stress superposition effect are fully investigated by a theoretical analysis and finite element simulation. The simulation results of the precision grinding model are verified by experiments, which show that the proposed numerical analysis model is reasonable and the finite element analysis process is feasible.

scholarly journals Effect to the Surface Composition in Ultrasonic Vibration-Assisted Grinding of BK7 Optical Glass

2020 ◽  
Vol 10 (2) ◽  
pp. 516 ◽  
Author(s):  
Pei Yi Zhao ◽  
Ming Zhou ◽  
Xian Li Liu ◽  
Bin Jiang
Keyword(s):  
Surface Roughness ◽  
Ultrasonic Vibration ◽  
Material Removal ◽  
Surface Composition ◽  
Rotation Speed ◽  
Optical Glass ◽  
Machined Surface ◽  
Spindle Rotation ◽  
Ultrasonic Vibration Assisted Grinding ◽  
Ductile Removal

Because of the changes in cutting conditions and ultrasonic vibration status, the proportion of multiple material removal modes are of uncertainty and complexity in ultrasonic vibration-assisted grinding of optical glass. Knowledge of the effect of machined surface composition is the basis for better understanding the influence mechanisms of surface roughness, and also is the key to control the surface composition and surface quality. In the present work, 32 sets of experiments of ultrasonic vibration-assisted grinding of BK7 optical glass were carried out, the machined surface morphologies were observed, and the influence law of machining parameters on the proportion of different material removal was investigated. Based on the above research, the effect of surface composition was briefly summarized. The results indicated that the increasing of spindle rotation speed, the decreasing of feed rate and grinding depth can improve the proportion of ductile removal. The introduction of ultrasonic vibration can highly restrain the powdering removal, and increase the proportion of ductile removal. Grinding depth has a dominant positive effect on the surface roughness, whereas the spindle rotation speed and ultrasonic amplitude both have negative effect, which was caused by the reduction of brittle fracture removal.

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