scholarly journals Surface and Subsurface Quality Assessment of Polished Lu2O3 Single Crystal Using Quasi-Brewster Angle Technique

2021 ◽  
Vol 9 ◽  
Author(s):  
Chengyuan Yao ◽  
Wanfu Shen ◽  
Xiaodong Hu ◽  
Chunguang Hu
Keyword(s):  
Single Crystal ◽  
High Sensitivity ◽  
Brewster Angle ◽  
Precision Machining ◽  
Polished Surface ◽  
Processing Scheme ◽  
Optical Profilometer ◽  
Ultra Precision ◽  
Consistency Of The Test

The sesquioxide Lu2O3 single crystal has attracted tremendous attention as potential host material for high-power solid-state lasers. As polishing is the terminal process of conventional ultra-precision machining, the quality of polished crystal directly impacts the crucial performance indicators of optics. The high melting point of Lu2O3 single crystal makes crystal preparation difficult. Therefore, investigations on the surface/subsurface quality inspection of polished Lu2O3 single crystal are scarce. In this paper, we utilize the quasi-Brewster angle technique (qBAT) based on ellipsometry to inspect the quality of polished Lu2O3 single crystal, achieving fast, non-destructive, and high-sensitive surface/subsurface damage assessment. A systematic crystal processing scheme is designed and polished Lu2O3 crystal samples are obtained. To verify the results of qBAT, the surface and subsurface quality are tested using optical profilometer and transmission electron microscope, respectively. The consistency of the test results demonstrates the feasibility, high sensitivity, and accuracy of the qBAT. To our knowledge, this is the first time that the qBAT is applied to investigate the polished surface/subsurface quality of Lu2O3 single crystal. In conclusion, this method provides a powerful approach to the high-precision characterization of the surface/subsurface quality of Lu2O3 single crystal, and has significant potential for material property study and process optimization during ultra-precision machining.

Machine Integrated Measurement of Ultra Precision Machined Specular Non-Rotational Symmetrical Surfaces

2014 ◽  
Vol 907 ◽  
pp. 277-289 ◽  
Author(s):  
Eckart Uhlmann ◽  
Gerhard Häusler ◽  
Christian Röttinger ◽  
Evelyn Olesch ◽  
Christian Faber ◽  
...  
Keyword(s):  
Machine Tool ◽  
Optical Measurement ◽  
Installation Space ◽  
Precision Machining ◽  
Test Surface ◽  
Full Field ◽  
Rotationally Symmetric ◽  
Ultra Precision ◽  
Height Data

In this paper, current results of a research project combining ultra precision machining and optical measurement are presented. The goal is to improve the quality of specular freeform surfaces manufactured by ultra precision slow slide servo turning by running appropriate correction cycles on the basis of machine integrated measurements. These measurements are conducted using the principle of Phase Measuring Deflectometry (PMD) in order to optically acquire full-field 3D-height data. For this purpose, a special setup the so called Mini PMD that can be operated within the limited installation space of an ultra precision machine tool has been designed and implemented. Results of machine integrated measurements of a specular non-rotational symmetrical surface are presented. Furthermore, using Mini PMD and a rotationally symmetric test surface, a complete correction cycle is demonstrated without the necessity of taking the workpiece off the machine for measurement.

Micro-Quality Control on Ultra-Precision Machining of Sapphire Substrates

2010 ◽  
Vol 102-104 ◽  
pp. 738-741
Author(s):  
Hai Zhou ◽  
Li Gang Bai ◽  
Dai Pin Wang
Keyword(s):  
Surface Roughness ◽  
Ph Value ◽  
Diamond Wheel ◽  
Precision Machining ◽  
New Approach ◽  
Sapphire Substrates ◽  
Ductile Mode ◽  
Ultra Precision ◽  
Main Factors

This paper proposed a new approach to control the micro-quality of sapphire substrate, in order to grow GaN on substrate. The main factors that influence macro-quality are the method of slicing, grinding and polishing. Thread speed of slicing is less than 0.5m/s. Ductile mode grinding of substrate is achieved by #3000 diamond wheel and feed of 1μm/r. The suitable polishing conditions are that the SiO2 grain size is less than 10nm, the concentration SiO2 is 3％, pH value of polishing liquid is 10.5 and polishing stress is 190Pa. The undamaged substrates have been obtained steadily. The surface roughness RMS is less than 0.4 nm.

Research on Precision Mirror Machining Technology for W-Mo Alloy

2011 ◽  
Vol 487 ◽  
pp. 303-307
Author(s):  
Jia Liang Guan ◽  
H.W. Lu ◽  
X.H. Xiao ◽  
Y.C. Wu ◽  
Z.D. Chen
Keyword(s):  
Surface Quality ◽  
Formation Mechanism ◽  
Rotational Speed ◽  
Precision Machining ◽  
Work Piece ◽  
Mirror Surface ◽  
Precision Grinding ◽  
Elid Grinding ◽  
Ultra Precision

A new way of precision machining was studied through the experiments of Electrolytic In-Process Dressing (ELID) precision grinding and ultra precision lapping and polishing for W-Mo metal alloy. First a 22nm(Ra) surface was obtained through the ELID grinding, last a 11nm(Ra) surface was obtained after the process of lapping and polishing with 0.1～0.3 N/cm2pressure, 60～100 r/min rotational speed and other optimized parameters. Meanwhile, the formation mechanism of ultra precision mirror surface of the alloy was also analyzed. The experiments prove surface quality of the work piece was guaranteed by ELID grinding, and which was also greatly affected by some parameters in lapping and polishing such as pressure, rotational speed.

scholarly journals Design and Manufacturing of a High-Sensitivity Cutting Force Sensor Based on AlSiCO Ceramic

Micromachines ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 63
Author(s):  
Taobo Gong ◽  
You Zhao ◽  
Yulong Zhao ◽  
Lukang Wang ◽  
Yu Yang ◽  
...  
Keyword(s):  
Cutting Force ◽  
High Speed ◽  
High Sensitivity ◽  
Force Sensor ◽  
High Price ◽  
Precision Machining ◽  
Force Sensors ◽  
Machining Accuracy ◽  
Status Monitoring ◽  
Ultra Precision

On-line cutting force measurement is an effective way to monitor processing quality, improve processing accuracy, and protect the tool. In high-speed and ultra-precision machining, status monitoring is particularly necessary to ensure machining accuracy. However, the cutting force is very small in high speed and ultra-precision machining. Therefore, high-sensitivity cutting force sensors are needed. Current commercial cutting force sensors have defects such as large volume, low compatibility, and high price. In particular, the sensitivity of cutting force sensor needs to be improved for high-speed and ultra-precision machining status monitoring. This paper provides a possible solution by embedding the sensor in the tool and selecting sensitive materials with high piezoresistive coefficient. In this paper, the structural design of the sensor and the fabrication of the sensitive material SiAlCO ceramic are carried out, and then the sensor is packaged and tested. The test results show that the cutting force sensor’s sensitivity was as high as 219.38 mV/N, which is a feasible way to improve cutting force sensor’s compatibility and sensitivity.

Ultra-Precision Machining of Stainless Steel and Nickel with Single Crystal 4H and 6H Boule SiC

2010 ◽  
Vol 645-648 ◽  
pp. 853-856 ◽  
Author(s):  
Wolfgang J. Choyke ◽  
B. D'Urso ◽  
Fei Yan ◽  
Robert P. Devaty
Keyword(s):  
Stainless Steel ◽  
Single Crystal ◽  
Cutting Tools ◽  
Precision Machining ◽  
Average Roughness ◽  
Flat Surfaces ◽  
Diamond Cutting Tools ◽  
Single Crystal Diamond ◽  
Single Crystal Sic ◽  
Ultra Precision

Ultra-precision machining is dominated by single-crystal diamond cutting tools, and is typically applied to a narrow range of materials, particularly aluminum and copper. Single-crystal SiC can be comparable to some diamonds in hardness and thermal conductivity, while potentially having superior chemical and thermal stability, yet it has not been explored as a cutting tool for ultra-precision machining. We made two cutting tools with single-crystal SiC, one with sharp corners and one with a large circular radius, and used them to cut flat surfaces on two materials, 316 stainless steel and nickel. These materials generally cause unacceptably rapid diamond tool wear. We report the average roughness of the resulting surfaces cut with single-crystal 4H and 6H SiC tools.

Ultra-Precision Machining Technology Based on Dynamic Minimum Thickness of Cut for Machined Single Crystal Materials

2011 ◽  
Vol 138-139 ◽  
pp. 1246-1250
Author(s):  
Ji Cai Kuai
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Single Crystal ◽  
Surface Quality ◽  
Cutting Parameters ◽  
Precision Machining ◽  
Minimum Thickness ◽  
Single Crystal Copper ◽  
Ultra Precision ◽  
Relationship Of

The dynamic minimum thickness of cut for the ultra-precision machining surface quality is important influence. Between tool and the workpiece for the friction coefficient were analysised, the relationship of the friction coefficient and the MTC were discussed, and the MTC and its effects on surface roughness were a theoretical analysised and experimental verification with processed single crystal copper and single crystal aluminum by AFM’s diamond tip. The results show: the MTC of single-crystal copper (single crystal aluminum) is 5.2nm (8.2nm) in stable cutting conditions. Further processing single crystal copper (ingle crystal aluminum) with cutting thickness of 5.2nm (8.2nm), and the surface roughness Ra160nm (Ra110nm) is obtained. So the MTC is evolving with the friction coefficient and the force ratio, theoretical MTC tends to be minimal value then before the adhering effect to reach remarkable. Appropriate adjustments cutting parameters, the cutting process can always micro-cutting phase to reach the steady-thin chip, and no plowing phenomenon. So the surface residues highly were reduced and higher surface quality was achieved.

Computer Simulation on the Motion Tracks of Ice Fixed Abrasives Polishing

2010 ◽  
Vol 426-427 ◽  
pp. 376-380 ◽  
Author(s):  
Yu Li Sun ◽  
Dun Wen Zuo ◽  
Jun Li ◽  
Wen Zhuang Lu ◽  
Z.Z. Yu
Keyword(s):  
Computer Simulation ◽  
Silicon Wafer ◽  
Size Range ◽  
Precision Machining ◽  
Speed Ratio ◽  
Polishing Process ◽  
Polishing Pad ◽  
Ultra Precision

Ice fixed abrasives (IFA) polishing is a novel ultra-precision machining method. The motion tracks of abrasives during IFA polishing have an important effect on the quality of the machined silicon wafer. Firstly, the motion tracks of IFA polishing are theoretically analyzed in this paper. It is founded that the paths of any point in the IFA polishing pad relative to the wokpiece are a group of cycloids. Then, the motion tracks of single abrasive and multiple abrasives in the IFA polishing pad are simulated respectively. The results show that increasing the eccentricity is beneficial to the enlargement of the size range of polishing process. With the increasing of the speed ratio between the IFA polishing pad and the workpiece, the abrasive at higher speed can leave longer tracks on the workpiece than that at lower speed at the same time. The more the abrasives, the more uniform the mark density under the influence of more abrasives.

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