What is the amount of cutting in CNC machining? What is tool radius compensation?

In CNC processing, there is a called the amount of knife, what does this refer to? The size of the knife is mainly limited by the machine tool, workpiece and tool stiffness, the selection principle is to meet the requirements of the process and process system stiffness permit conditions, choose as large as possible to improve the processing efficiency.

In order to ensure CNC machining accuracy and surface roughness, a margin of 0.2-0.5mm should be left for finishing. In rough machining, the cutting method is often used to cut the allowance. In CAM programming, the cutting depth and the maximum step width of each layer need to be set, but the actual step is often related to the shape of the workpiece.

In CNC finishing, the choice of cutting amount is related to the surface roughness. CAM software usually provides two parameters to control the surface roughness: step width and residual height.

Using interval width control surface roughness, the smaller the interval width, the smaller the surface roughness, but the machining path and the time will be greatly extended, so the interval width should not be set too small, in practice can be changed by semi-finishing and finish machining tool path method (into two orthogonal relation) to improve the surface quality. When the residual height is used to control the surface roughness, the step width is automatically adjusted according to the workpiece shape.

In the CNC machining process will also hear about tool radius compensation, so what is tool compensation?

The tool radius compensation concept is just like the tool length compensation is basically not considered when programming, because with the tool radius compensation, we can not think too much about the tool diameter. Tool length compensation is applicable to all tools, while tool radius compensation is generally only used for milling cutters.

When CNC machining the outer or inner contour of the workpiece, the tool radius compensation is used, when face milling cutter machining the end face of the workpiece, only the tool length compensation. Because cutter radius compensation is a difficult instruction to understand and use, many people are reluctant to use it in programming. But once we understand and master it, the use of our programming and processing will bring great convenience.