The mechanical manufacturing process generally refers to the sum of the mechanical processing process of the parts and the assembly process of the machine. To formulate the mechanical processing process, it is necessary to admit that the workpiece has to go through several processes and the sequence of the processes. Only the first process name is listed. The brief process of its processing sequence is called the process route.

The formulation of the process route is to formulate the overall layout of the process. The primary task is to select the processing method of each surface, recognize the processing order of each surface, and the number of processes in the entire process. The drafting of the process route must follow certain principles.

1. The principle of formulating the process route of machined parts:

1. Machining the datum surface first: During the machining process of the part, the surface as the positioning reference should be machined first, so as to provide a precise reference for the processing of the subsequent process as soon as possible. It's called "baseline look-ahead".

2. Divide the processing stages: Surfaces with high processing quality requirements are divided into processing stages, which can generally be divided into three stages: roughing, semi-finishing and finishing. The first is to ensure the quality of processing; it is conducive to the rational use of equipment; it is convenient to arrange the heat treatment process; and it is convenient to find blank defects.

3. Face first and then hole: For parts such as box, bracket and connecting rod, the plane should be machined first and then the hole should be machined. In this way, the processing hole can be positioned on the plane, the azimuth accuracy of the plane and the hole can be ensured, and the processing of the hole on the plane can be facilitated.

4. Finishing processing: The finishing processing of the primary surface (such as grinding, honing, fine grinding and rolling processing, etc.) should be carried out at all stages of the process. The surface finish after processing is above Ra0.8um, and fine collisions will damage the surface;

In Japan, Germany and other countries, after finishing, it must be protected with flannel. It is not allowed to directly touch the workpiece with hands or other objects to prevent the surface of finishing from being damaged due to the transfer and installation between processes.