Technical difficulties:

1) High dimensional requirements: key position, parallelism, flatness, verticality, symmetry and contour should be within 0.003 mm;

2) Difficult assemble and high assembly precision. It has a total of forty-five machining operations and many assembly sizes with a tolerance within 0.003 mm.

3) The whole set of tooling processing technology includes CNC, grinding, turning, electric machining and honing processing.