The principles to be followed in the processing of precision parts are as follows:
  
1. Reference first: the reference surface is processed first. During the mechanical processing of the parts, the appearance as the positioning reference should be processed first, so as to provide a precise reference for the processing of subsequent processes as soon as possible.
   

2. Division of processing stages: The appearance of high-quality mechanical processing is divided into processing stages, which can generally be divided into three stages of roughing, semi-finishing and finishing. The main purpose is to ensure the processing quality; it is beneficial to the scientific application of equipment; it is convenient to arrange the heat treatment process; and it is easy to find the rough defects.
 
3. Face first and then hole: For parts such as box, bracket and connecting rod, the surface should be machined first and then the hole. In this way, the holes can be positioned and processed in a plane to ensure the position accuracy of the plane and the holes, and it is convenient for the processing of the holes on the plane.

4. Finishing: The finishing of the main surface, such as grinding, honing, finishing, rolling, etc., should be placed at the end of the process route. The general principles for formulating the processing route for precision parts and the formulation of the process regulations for precision parts can be roughly divided into two links.