Multiscale Modeling and Analysis of an Ultra-Precision Damage Free Machining Method

2016 ◽  
Vol 07 (01) ◽  
pp. 1640004
Author(s):  
Chaoliang Guan ◽  
Wenqiang Peng

Under the condition of high laser flux, laser induced damage of optical element does not occur is the key to success of laser fusion ignition system. US government survey showed that the processing defects caused the laser induced damage threshold (LIDT) to decrease is one of the three major challenges. Cracks and scratches caused by brittle and plastic removal machining are fatal flaws. Using hydrodynamic effect polishing method can obtain damage free surface on quartz glass. The material removal mechanism of this typical ultra-precision machining process was modeled in multiscale. In atomic scale, chemical modeling illustrated the weakening and breaking of chemical bond energy. In particle scale, micro contact modeling given the elastic remove mode boundary of materials. In slurry scale, hydrodynamic flow modeling showed the dynamic pressure and shear stress distribution which are relations with machining effect. Experiment was conducted on a numerically controlled system, and one quartz glass optical component was polished in the elastic mode. Results show that the damages are removed away layer by layer as the removal depth increases due to the high damage free machining ability of the HEP. And the LIDT of sample was greatly improved.

Author(s):  
Jie Chen ◽  
Jun Wang

Hexagon-shaped Zn oxide nano-pole films with terraces and steps have been successfully fabricated by means of a combined approach involving sol-gel process, high-temperature heat treatment, and the hydrothermal method. The surface chemistry and morphological features of the films were characterized by means of x-ray photoelectron spectroscopy and scanning electron microcopy. All the diffraction peaks in x-ray diffraction pattern match with those of the hexagonal wurtzite phase of Zn oxide. Transmittance measurements show that the optical transmittance of the sample synthesized at 520°C on quartz glass substrate is the highest, reaching about 65% in the visible-light region. Based on the detailed structural characterization and the nucleation-growth kinetics, we find that the whole crystallization process of wurtzite Zn oxide nano-poles includes nanocatalysis and layer-by-layer growth mechanism. The present study provides an important understanding of the growth mechanism for nano-pole synthesis of Zn oxide and related materials.


2004 ◽  
Vol 471-472 ◽  
pp. 473-476 ◽  
Author(s):  
Ju Long Yuan ◽  
Fei Yan Lou ◽  
Zhi Wei Wang ◽  
M. Chang ◽  
W.P. Du ◽  
...  

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.


2012 ◽  
Vol 497 ◽  
pp. 1-5
Author(s):  
Xiao Dan Xie ◽  
Yong Li ◽  
Cam Vinh Duong ◽  
Ahmed Al-Zahrani

Traditionally, single point diamond turning (SPDT) can not process ferreous metals because of acute tool wear. Ultrasonic vibration-assisted cutting(UVC) provides a promising solution for the problem. In this paper, for the aim of directly obtaining mirror surface on die steels, UVC method was used combining with SPDT process. Experiments were carried out on an ultra precision turning machine, cutting parameters and vibration parameters were well-chosen, and two kind of feed rates, two kinds of prevailing die steels were experimented. Mirror surfaces were successfully achieved on face turning, with the best roughness of Ra16.6nm. And the surface roughness, surface texture and tool wear in machining process were discussed.


2012 ◽  
Vol 426 ◽  
pp. 396-399 ◽  
Author(s):  
Xiao Zong Song ◽  
Yong Zhang ◽  
Fei Hu Zhang

In this paper, ultra-precision shaping and ultra-smooth polishing investigations have been done upon a high-purity quartz glass substrate with an aspheric surface in nanoparticle colloid jet machining, which is an ultra smooth surface processing technique utilizing surface chemical reaction between work surface atoms and nanoparticles to remove the uppermost surface atoms. The shaping and polishing characters of high-purity quartz glass in nanoparticle colloid jet machining has been researched. The surface profile of the high-purity quartz glass workpiece before and after shaping has been measured by surface profilometer. And the surface microscopic morphological characteristics of high-purity quartz glass surface polished by nanoparticle colloid jet machining have been observed by atomic force microscopy (AFM). The measurement results indicate that nanoparticle colloid jet machining has good shaping ability for surface shape correction in ultra-precision machining. And the AFM observation results show that the roughness of the high-purity quartz glass surface has been reduced from 1.919 nm RMS to 0.784 nm RMS by nanoparticle colloid jet machining.


2014 ◽  
Vol 53 (29) ◽  
pp. 6913 ◽  
Author(s):  
Wenqiang Peng ◽  
Chaoliang Guan ◽  
Shengyi Li

2018 ◽  
Vol 12 (2) ◽  
pp. 145-153 ◽  
Author(s):  
Toshiro Doi ◽  

SiC, GaN, and diamond are known as super-hard-to-process substrate for next-generation green devices. In this paper, we report on some breakthrough in developing highly efficient processing for such hard-to-process materials, for which we propose improvements in conventional processing, and innovative processing. As part of our project, we developed a “dilatancy pad®” that can efficiently produce high-quality surfaces as well as a high-rigidity, high-speed and high-pressure processing machine. We also designed and prototyped “plasma fusion CMP®,” which is an innovative processing technology fusing CMP (Chemical Mechanical Polishing) with P-CVM (Plasma Chemical Vaporization Machining) to machine super-hard diamond substrates that are considered indispensable for future devices. Before the advent of “singularities” by 2045, super-hard-to-process substrates and ultra-precision polishing technology will become more and more essential.


2014 ◽  
Vol 633-634 ◽  
pp. 615-619
Author(s):  
Su Juan Wang ◽  
Su Et To ◽  
Xin Chen ◽  
Jian Qun Liu

This paper studies the development of cutting strategy in the fabrication of freeform surface in ultra-precision raster milling (UPRM). The tasks of developing cutting strategy in freeform machining involve in the selection of cutting parameters and the planning of tool paths. An integrated system is built in this study to develop the cutting strategy, automatically generate NC program, simulate the tool paths and machining process, as well as make predictions for the machining time and the surface quality of the raster milled freeform surface. Experiment is conducted to verify the developed system and the experimental results show that the system is applicable for the machining of freeform surface in UPRM. This study therefore contributes to avoiding the need to conduct expensive and time consuming trial cutting tests to ensure the product quality in the freeform machining.


1989 ◽  
Vol 165 ◽  
Author(s):  
Masataka Hirose ◽  
Seiichi Miyazaki

AbstractThe early stages of thin film deposition from the rf glow discharge of SiH4 or SiH4 + NH3 have been studied by analysing the structure of silicon based multiiayers consisting of hydrogenated amorphous silicon (a-Si:H, 10 – 200 A thick) and stoichiometric silicon nitride (a-Si3N4:H, 25 – 250 A) alternating layers. The x-ray diffraction, its rocking curve and x-ray interference of the multilayers have shown that the amorphous silicon/silicon nitride interface is atomically abrupt and the surfaces of the respective layers are atomically flat regardless of substrate materials. This indicates that the precursors impinging onto a substrate from the gas phase homogeneously cover the growing surface and the layer by layer growth proceeds on atomic scale. In the plasma deposition of the covalently bonded semiconductors and insulators, the island formation on a substrate surface at the beginning of the thin film growth is very unlikely.


Optik ◽  
2018 ◽  
Vol 156 ◽  
pp. 374-383 ◽  
Author(s):  
Wenqiang Peng ◽  
Shengyi Li ◽  
Chaoliang Guan ◽  
Yuan Li ◽  
Xudong Hu

Sign in / Sign up

Export Citation Format

Share Document