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Cao J.,CAS Shanghai Institute of Optics and fine Mechanics | Cao J.,University of Chinese Academy of Sciences | Yang M.,CAS Shanghai Institute of Optics and fine Mechanics | Wei C.,CAS Shanghai Institute of Optics and fine Mechanics | And 4 more authors.
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2015

In order to study the effects of different rogue particles on the scratches, and establish the relationship between the rogue particle size and the scratch topography, experiments have been carried out. During the process of phosphate neodymium polishing, three different sizes of corundum, cerium oxide agglomerate and polished powder are introduced as rogue particles. Data of scratch topography is analyzed statistically. The results show that brittle scratches, plastic scratches and mixed scratches all exist, among which brittle scratches account for a large proportion; scratches caused by cerium oxide agglomerate and polished powder are shallow and few, while scratches caused by corundum are deep and many; the scratch density and scratch length caused by corundum of different sizes increase with the increasing of particle size; distribution of scratch widths caused by different sizes of corundum is similar to the distribution of the size of rogue particle, shown as Gaussian distribution. Using the model proposed by T. Suratwala, mechanism of scratch generating during phosphate neodymium glass polishing is investigated. It is illustrated that the width and length of scratches increase with the increasing of rogue particle size. ©, 2014, Science Press. All right reserved. Source


Ji J.,CAS Shanghai Institute of Optics and fine Mechanics | Ji J.,University of Chinese Academy of Sciences | Wei C.,CAS Shanghai Institute of Optics and fine Mechanics | Hu C.,CAS Shanghai Institute of Optics and fine Mechanics | And 3 more authors.
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2014

The edge effect appears at the edge of workpiece as a result of the uneven distribution of pressure in computer controlled optical surfacing (CCOS) and this restricts the fabrication accuracy in practice seriously. The edge effect has become one of the urgent problems of numerical control machining technology. Theoretical simulation and experimental verification are done based on liner pressure distribution model and skin pressure distribution model. The experimental results show that when the distance between the workpiece and the tool borders is relatively large (the distance is 1/3 of aperture of removal function in experiment) or short (the distance is 1/24 of aperture of removal function in experiment). Little difference between removal functions based on both of the models is observed and the effectiveness of the models is proved that when the distance is medium(the distance is 1/6 of aperture of removal function in experiment), the removal function based on linear model is closer to the experimental result and the skin model has a biggr deviation with the experiment result in the central area. ©, 2014, Science Press. All right reserved. Source


Xu J.,CAS Shanghai Institute of Optics and fine Mechanics | Xu X.,CAS Shanghai Institute of Optics and fine Mechanics | Xu X.,Shanghai Hengyi Optics and Fine Mechanics Co. | Wei C.,CAS Shanghai Institute of Optics and fine Mechanics | And 5 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

The effect of deep HF etching on the surface quality and figure of fused silica optics has been investigated systematically. Fused silica samples (100 mm in diameter x 10 mm thick) were manufactured using the conventional grinding and polishing process. These processed samples are etched with different removal depth. Initially, the surface quality of fused silica samples is characterized in terms of surface roughness and surface defects. Many digs not more than 1ìm deep are emerged which originates from the micron grinding cracks and crack pits. These digs worsened the surface roughness and frosted the sample. While submillimeter subsurface damage exposed through etching appear as sparkling dots under the high power lamp. The average total length of millimeter scratches on single surfaces is over 200 mm. Not all millimeter scratches could be exposed until removal depth of up to 2 μm. Finally, the surface figure behavior during deep etching has also been figured out. Etching on the edge of the upper surface of samples placed horizontally went faster than on the inside parts. The surface of samples placed vertically assumed a more complicated removal distribution, which can be bothexplained in terms of "fringe tip effect". For the change of surface figure PV, the initial surface figure feature plays an important role as well as the etching removal distribution. © 2015 SPIE. Source

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