Share Email Print
cover

Proceedings Paper

Crack depth uniformity control techniques for large scale fused silica optics in grinding process
Author(s): Lian Zhou; Nan Zheng; Xianhua Chen; Mincai Liu; Qinghua Zhang; Jian Wang; Jie Li
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

In order to improve the overall efficiency of machining and the defect quality of large aperture fused silica optics, it’s necessary to strictly control the crack defects and their depth uniformity in the first grinding process. Firstly, the morphology of three typical defects affecting the uniformity of crack depth was analyzed, which were scattered superficial sand holes, continuous linear defects and dotted linear defects. Then according to the morphology, the causes were investigated and the control techniques were proposed. The scattered superficial sand holes were caused by the large size glass powder, the diamond particles dropped from the grinding wheel and other foreign body impurities in the grinding fluid, which had been squeezed into the surface of the element by the grinding wheel. Through the clean filtration of grinding fluid, the quantity of such defects could be effectively reduced. The continuous linear defects were caused by stress concentration at the two sharp edges of the grinding wheel. Arcing the two sides of wheel could reduce the machining stress at the edges and avoid the occurrence of continuous linear defects. The dotted linear defects were caused by the stress concentration of the grooves on the surface of the wheel during grinding. After optimizing the dressing parameters to reduce the dressing force and avoid the grains of dressing wheel being embedded into the grinding wheel surface, all the grooves on the wheel surface and all the dashed line defects on the element surface disappeared practically. At the last, after integrating all the above control techniques, the grinding experiment of large scale fused silica optics was carried out. The scattered superficial sand holes, continuous linear defects and dotted linear defects on the surface of element after grinding were obviously alleviated. The crack depth of the whole aperture was between 4μm and 7μm. All the results indicated that the control techniques were efficacious.

Paper Details

Date Published: 10 May 2019
PDF: 10 pages
Proc. SPIE 11068, Second Symposium on Novel Technology of X-Ray Imaging, 1106815 (10 May 2019); doi: 10.1117/12.2524151
Show Author Affiliations
Lian Zhou, Research Ctr. of Laser Fusion (China)
Nan Zheng, Research Ctr. of Laser Fusion (China)
Xianhua Chen, Research Ctr. of Laser Fusion (China)
Mincai Liu, Research Ctr. of Laser Fusion (China)
Qinghua Zhang, Research Ctr. of Laser Fusion (China)
Jian Wang, Research Ctr. of Laser Fusion (China)
Jie Li, Research Ctr. of Laser Fusion (China)


Published in SPIE Proceedings Vol. 11068:
Second Symposium on Novel Technology of X-Ray Imaging
Yangchao Tian; Tiqiao Xiao; Peng Liu, Editor(s)

© SPIE. Terms of Use
Back to Top
PREMIUM CONTENT
Sign in to read the full article
Create a free SPIE account to get access to
premium articles and original research
Forgot your username?
close_icon_gray