When machining parts on CNC lathes, the process shall be divided according to the principle of process concentration, and the processing of most or all of the surfaces shall be completed as much as possible in one setup. According to different structural shapes, the outer circle, end face or inner hole, and end face clamping are usually selected, and the design reference, process reference, and programming origin are unified. In batch production, the following methods are commonly used to divide the process.
1, according to the part processing surface division process
That is to say, the part of the process that completes the same profile is a process. For parts that have many and complex machining surfaces, they can be divided into multiple processes according to their structural characteristics (such as internal shape, shape, curved surface, and plane).
The surface with higher requirements of position accuracy is completed in a single clamping so that the errors caused by multiple positioning and clamping do not affect the position accuracy. As shown in Figure 1, according to the technical characteristics of the parts, the outer and inner contours of the rough and finish machining are each completed in a single process, reducing the number of clamping and concentricity.
2, according to rough, fine processing division process
That part of the process completed in roughing is a process, and that part of the process completed in finishing is a process. For parts with large blank allowance and high machining accuracy, the roughing car and the finishing car should be separated and divided into two or more processes. The roughing car is arranged on the CNC machine tool with low precision and high power, and the finishing car is arranged on the CNC machine tool with high precision.
This division method is suitable for parts with large deformation after processing and parts that need to be separated by roughing and finishing. For example, blanks are parts for castings, weldments or forgings.
Divide the process by the type of tool used
3, according to the type of tool used to divide the process
The part of the process completed with the same tool is a process, this method is suitable for the workpiece surface to be machined more, the machine continuous working time is longer, the preparation and inspection of the processing program is more difficult.
4, according to the number of installation process
The part of the process completed in one installation is an operation. This method is suitable for workpieces with few processing contents and can reach the state to be inspected after processing is completed