日本一区二区三级在线,中文字幕有码人妻在线,91视色国内揄拍国内精品人妻,日本一区二区在线播放视频,日韩精品一区二区免费,精品亚洲av乱码一区二区三区,日本视频在线播放一区二区,丰满老熟女性生活视频,国产激情自拍在线视频,亚洲熟女乱一区二区三区

Precision machining is a machining method with machining accuracy up to 1 micron. Precision machining method mainly includes fine turning, fine boring, fine milling, fine grinding and grinding technology. Under strictly controlled environmental conditions, the use of precision machine tools and precision measuring tools and measuring instruments to achieve. Machining accuracy of 0.1 micron or more is called ultra precision machining. In the aerospace industry, precision machining is mainly used to process precision mechanical parts in aircraft control equipment, such as hydraulic and pneumatic servomechanics.