cnc processing order arrangement principle

According to the structure of the part, the state of the blank and the needs of positioning and clamping, the arrangement of the CNC machining sequence is considered, emphasizing that the rigidity of the workpiece is not destroyed. The sequence of the program should generally follow the following principles:

One: Basic priority principle

At the beginning of processing, the fine base surface should be machined first, because the more accurate the reference surface, the higher the clamping error. The smaller it is, so the machining of any CNC precision parts must first be roughed, semi-finished, and if necessary, finished. For example, the box parts generally process the positioning plane and two positioning holes first, and then use the plane and positioning holes as the finishing reference to process the hole system and other planes. The principle of improving the machining accuracy is to arrange the machining of the base surface and the main surface.

Second: Rough first and then fine

The machining sequence of each side shall be smoothed in the order of rough machining and finishing machining. , in order to gradually improve the precision of the machined surface and reduce the surface roughness.

Three: The principle of first priority and second priority

The precision of the surface of the part and the assembly surface is relatively high, which belongs to the main surface and should be first Machining for early detection of possible defects on the main surface of the blank. For surfaces such as empty surfaces, keyways, closed screw holes, and light and empty surfaces, the accuracy requirements are not high, and they are secondary surfaces, which can be interspersed. Generally, finishing is arranged after the main machining surface reaches a certain accuracy.

Four: The principle of front and back

For cabinets, brackets and body parts, the plane dimensions are larger, generally the first machined surface, Post-processing holes and other dimensions. Therefore, on the one hand, the machined plane is used for positioning, which is stable and reliable; on the other hand, it is easier to machine the hole on the machined plane, and the machining accuracy of the hole can be improved.

Five: Preconceived principle

That is to say, the inner cavity machining process is performed first, and then the outer shape machining process is performed.

Six: The processing of the previous process does not affect the positioning and clamping of the next process.

Seven: Use the same installation method or the same tool to process the process, preferably continuous to reduce the number of repeated positioning.

Eighth: For multiple processes in the same installation process, the process that less damages the rigidity of the workpiece should be arranged first. In addition, when arranging the CNC machining sequence, pay attention to the arrangement of the undercuts, chamfers and other operations.