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.