Study on Ultra-Precise Machining of CLBO Crystal

2006 ◽  
Vol 304-305 ◽  
pp. 398-402 ◽  
Author(s):  
Xun Lv ◽  
Ju Long Yuan ◽  
Yong Dai ◽  
Jia Jin Zheng ◽  
Zhao Zhong Zhou ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Crystal Surface ◽  
Technical Problem ◽  
Damage Threshold ◽  
Laser Wavelength ◽  
Precision Machining ◽  
Lithium Borate ◽  
Fundamental Laser ◽  
Ultra Precision

Cesium Lithium Borate (CsLiB6O10 or CLBO) is the most effective non-linear crystal which generates ultraviolet harmonics of the Nd:YAG fundamental laser wavelength. In order to enhance the damage threshold, low CLBO surface roughness, by ultra-precision machining, is needed. Because the CLBO crystal has easy hydroscopic reaction and micro scratches in machining, ultra-precise machining of the CLBO crystal is a difficult technical problem. In this paper, the new lapping slurry and polishing slurry are introduced. And the deliquescence degree of CLBO is fallen to lowest. A new working technology is also adopted. After rough polishing, the concentration of ultra-precision polishing slurry is increased properly. So does the ultra-precision polishing speed, and the wiping speed is faster than the deliquescence speed. The CLBO crystal surface roughness can achieve 1nm and keep the surface quality well.

Characterization of Cutting-Induced Heat Generation in Ultra-Precision Milling of Aluminium Alloy 6061

2013 ◽  
Vol 552 ◽  
pp. 201-206
Author(s):  
Su Juan Wang ◽  
Suet To ◽  
Xin Du Chen
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Heat Generation ◽  
Feed Rate ◽  
Dimensional Accuracy ◽  
Precision Machining ◽  
Machined Surface ◽  
Single Crystal Diamond ◽  
Ultra Precision ◽  
Alloy 6061

The technology of ultra-precision machining with single crystal diamond tool produces advanced components with higher dimensional accuracy and better surface quality. The cutting-induced heat results in high temperature and stress at the chip-tool and tool-workpiece interfaces therefore affects the materials and the cutting tool as well as the surface quality. In the ultra-precision machining of al6061, the cutting-induced heat generates precipitates on the machined surface and those precipitates induce imperfections on the machined surface. This paper uses the time-temperature-precipitation characteristics of aluminum alloy 6061 (al6061) to investigate the effect of feed rate on the cutting-induced heat generation in ultra-precision multi-axis milling process. The effect of feed rate and feed direction on the generation of precipitates and surface roughness in ultra-precision raster milling (UPRM) is studied. Experimental results show that heat generation in horizontal cutting is less than that in vertical cutting and a larger feed rate generates more heat on the machined workpiece. A smaller feed rate produces a better surface finish and under a larger feed rate, scratch marks are produced by the generated precipitates and increase surface roughness.

Effects of the Tool Angles on the Machined Surface Quality of KDP Crystal in Diamond Turning

2007 ◽  
Vol 364-366 ◽  
pp. 297-301 ◽  
Author(s):  
Jing He Wang ◽  
Ming Jun Chen ◽  
Shen Dong ◽  
Shi Qian Wang
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Rake Angle ◽  
Diamond Turning ◽  
Precision Machining ◽  
Machined Surface ◽  
Kdp Crystal ◽  
Factors Affecting ◽  
Ultra Precision ◽  
Back Angle

In the ultra-precision machining of KDP crystal, there are many factors affecting the surface quality[1-3]. The experiments show that the rake angle and back angle of the tool have significant effects on machined surface roughness. Therefore, an efficient way to improve the surface roughness is to select a proper negative rake angle. In this study, the ANSYS static analysis method was employed to analyze the stress field distribution within the whole cutting region. A finite element simulation model was set up to calculate the residual stresses variation with tool’s angles, which can be considered to select optimal rake and back angles in the ultra-precision machining of KDP crystal. Results show that the optimal tool rake angle and back angle are -49° and 7°, respectively. Finally, by using different tool angles to process KDP crystal and utilizing AFM to analyze the surface roughness, it can be found that the measurement results agree well with what are deduced from theoretical calculation.

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.

Research on Ultra-Precision Machining Technology for KTP

2004 ◽  
Vol 471-472 ◽  
pp. 473-476 ◽  
Author(s):  
Ju Long Yuan ◽  
Fei Yan Lou ◽  
Zhi Wei Wang ◽  
M. Chang ◽  
W.P. Du ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Frequency Conversion ◽  
Removal Rate ◽  
Nonlinear Coefficient ◽  
Damage Threshold ◽  
Green Laser ◽  
Machining Process ◽  
Polished Surface ◽  
Nonlinear Frequency ◽  
Ultra Precision

Potassium Titanium Oxide Phosphate (KTP) is a new nonlinear frequency-conversion crystal. It has chemical stability, high nonlinear coefficient, high damage threshold, easily-polished surface, and a broad transparency range. It is be used in solid green laser with medium and low power widely. The requirement for surface roughness is less than 1nm.In this paper, the removal rate and surface roughness are discussed with different velocity, pressure and size of abrasive powder. In order to satisfy the requirement, new polishing techniques with ultra-precision plane polishing machine (Nanopoli-100), and fine AL2O3, SiO2 powders are proposed in this study. The final surface roughness of the KTP is less than 1nm.The machining process and characteristics are also indicated.

A Study on Surface Quality of GaN with CMP Polishing Process

2011 ◽  
Vol 291-294 ◽  
pp. 1764-1767
Author(s):  
Wei Li ◽  
Ming Ming Ma ◽  
Bin Hu
Keyword(s):  
Surface Roughness ◽  
Particle Size ◽  
Gallium Nitride ◽  
Surface Quality ◽  
Chemical Reaction ◽  
Experimental Result ◽  
Precision Machining ◽  
Polishing Process

This paper introduced a polishing process for planarization of gallium nitride (GaN) wafer by polishing slurry that is made up by the chemical reaction with H2O2 solution and iron. Some different polishing parameters in the polishing process has been analyzed, which affect the surface quality of wafers, such as slurry particle size, polishing times, polishing slurry etc., and trying to improve the polishing process by optimization of the polishing parameters. The experimental result showed that this polishing method has an effect on the surface quality of GaN wafers, finally, the efficient and precision machining with surface roughness of GaN wafers of Ra0.81 nm has been gained by the CMP polishing process.

Research on Surface Roughness Prediction Model Based on Genetic Algorithm for Optical Ultra-Precision Machining

2007 ◽  
Vol 10-12 ◽  
pp. 369-373
Author(s):  
Jian Jun Du ◽  
Chi Fai Cheung ◽  
Suet To ◽  
Z.Y. Liu
Keyword(s):  
Numerical Simulation ◽  
Genetic Algorithm ◽  
Surface Roughness ◽  
Linear Regression ◽  
Precision Machining ◽  
Mathematics Model ◽  
Simulation Test ◽  
New Model ◽  
Roughness Prediction ◽  
Ultra Precision

In this paper a dynamic non-linear mathematics model is proposed to predict the surface roughness in optical ultra-precision machining, which can be automatically built by evoling computer program of genetic algorithm. The new model can improve the fitting and predicting accuracy, compared with the traditional linear regression model. The numerical simulation test proves the effectiveness and accuracy of new model.

Binderless-cBN as Cutting Material for Ultra-Precision Machining of Stainless Steel

2014 ◽  
Vol 1018 ◽  
pp. 107-114 ◽  
Author(s):  
Julian Polte ◽  
Mitchel Polte ◽  
David Lorenz ◽  
Dirk Oberschmidt ◽  
Heinz Sturm ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Surface Quality ◽  
Wear Mechanisms ◽  
Machine Tools ◽  
Experimental Studies ◽  
High Potential ◽  
Precision Machining ◽  
Workpiece Material ◽  
Ultra Precision ◽  
Direct Cutting

The ultra–precision cutting of steel materials is possible but needs modifications of machine tools or the workpiece material. One approach of actual research is the development of cutting materials that gives the opportunity for direct cutting of surfaces with ultra–precision quality. Binderless–cBN is here one of the most promising materials. The paper shows results of experimental studies with binderless–cBN as cutting material while turning stainless steel. Various investigations were carried out to determine the wear mechanisms. Furthermore, measurements are shown regarding the surface quality. The achieved results show the high potential ofbinderless–cBN as cutting material for the machining of steel.

Research on Elastic-Plastic Transition and Hardening Effect for Monocrystalline Silicon Surfaces

2014 ◽  
Vol 1027 ◽  
pp. 101-106
Author(s):  
Xiao Guang Guo ◽  
Chang Heng Zhai ◽  
Zi Yuan Liu ◽  
Liang Zhang ◽  
Zhu Ji Jin ◽  
...  
Keyword(s):  
High Frequency ◽  
Crystal Surface ◽  
Silicon Crystal ◽  
Silicon Surfaces ◽  
Precision Machining ◽  
Displacement Curve ◽  
Elastic Plastic ◽  
Ultra Precision ◽  
Load Displacement ◽  
Dynamics Method

Based on molecular dynamics method, a nanoindentation simulation of the silicon crystal is built and the load-displacement curve is drawn. According to the load-displacement curve, the elastic-plastic transition of silicon crystal is analyzed. The results show that the critical point in the elastic-plastic transition is between 15 and 20 angstroms. In addition, different crystal planes of silicon crystal are loaded for five cycles respectively; the nanohardness is calculated and the nanohardness curve is obtained. The results show that after the first plastic deformation of the silicon crystal surface is occurred, the surface will have a higher hardness and a higher elasticity. Therefore, in the ultra precision machining, in order to reduce the occurrence of damage, the depth of the processing should be controlled in the range of elasticity. Moreover, the method of small quantities in high frequency can increase mechanical properties on the surface.

Study on Semi-Fixed Abrasive Lapping of Ultra-Thin Silver Electrode Layer

2009 ◽  
Vol 69-70 ◽  
pp. 225-228
Author(s):  
Xun Lv ◽  
Ju Long Yuan
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
High Efficiency ◽  
Processing Parameters ◽  
Silver Electrode ◽  
Processing Load ◽  
Electrode Layer ◽  
Good Surface ◽  
Good Surface Quality ◽  
Ultra Precision

Silver electrode layer of piezoelectric ceramic transducer requires good surface quality and high efficiency. Efficiency of traditional lapping and polishing is very low. Ultra-precision grinding technology is also unsuitable for the thickness of workpiece is extremely thin. Semi bonded abrasive lapping is a new ultra-precision processing method. The new ultra-precise method can achieve good surface quality in short time, and removal stock of workpiece is small. In order to research the optimal technology of semi bonded abrasive lapping about silver electrode layer, this paper research several major processing parameters by experiments. The results show that appropriate processing load can obtain better surface roughness of silver electrode layer，and surface roughness of silver electrode layer has little change with different processing speed. By using ultra-fine semi bonded abrasive plate, 94.08KPa processing load and 40 rpm polishing speed, after 30 minutes, surface roughness of silver electrode layer is 11nm, and removal stock is 11.5μm.

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