What Are the Principles of CNC Precision Machining?

1. The principle of first machining of the datum plane of CNC precision machining

At the beginning of processing, the surface used as the finishing reference is always processed. Because the surface of the positioning reference is accurate, the clamping error is small. Therefore, in the processing of any part, the positioning reference surface is always roughed and semi-finished machining, and if necessary, CNC precision machining is required.

For example, shaft parts always carry out rough machining and semi-finish machining on the positioning reference surface, and then finish machining. For shaft parts, the center hole is always processed first, and then the hole system and other surfaces are processed based on the center hole surface and the positioning hole. If there is more than one datum surface, the processing of the datum surface should be arranged in accordance with the order of datum conversion and the principle of gradually improving the accuracy of CNC precision machining.

2. The principle of inside before outside of CNC precision machining

For precision sleeves, the coaxiality between the outer circle and the hole is required. Generally, the principle of hole before outer circle is adopted, that is, the outer circle is used as the positioning reference to machine the hole, and then the hole with higher precision is used as the positioning reference for CNC machining outer circle, which can ensure high coaxiality requirements between the outer circle and the hole, and the fixture structure used is also very simple.

3. The principle of CNC precision machining to reduce the number of tool changes

In CNC machining, the order of machining should be arranged as far as possible according to the order in which the tool enters the machining position.