What Is a Radius Cutter?

During the machining process of a CNC machine tool, it controls the trajectory of the tool center. For convenience, the user always compiles the machining program according to the part contour. Therefore, in order to process the required part contour, the tool center must be used for internal contour processing. Offset a tool radius value to the inside of the part; when performing external contour processing, the tool center must be offset to the outside of the part by a tool radius value. As shown in Figure 3-25. This kind of function that the NC device can automatically generate the tool center trajectory in real time according to the program compiled according to the part contour and the preset offset parameters is called the tool radius compensation function. In the figure, the solid line is the outline of the part to be processed, and the dotted line is the tool center trajectory. According to the ISO standard, when the tool center trajectory is to the right of the programmed trajectory (part contour) in the forward direction, it is called right tool compensation, and it is implemented with the G42 command; otherwise it is called left tool compensation, and it is implemented with the G41 command.

1. B knife repair

Features: The center path of the tool is connected by a circular arc.

Advantages: Simple algorithm and easy implementation.

Disadvantages:

(1) When machining the outer contour, the cutter will always cut at one point when the arc is connected.

(1) Because

1. After the tool nose radius is compensated, the tool will automatically deviate from the contour radius of the part. Therefore, the radius of the tool nose arc must be entered into the memory of the system. Generally take 0.8mm for rough machining, 0.4 mm for semi-finish machining, and 0.2mm for fine machining.
2. The shape of the turning tool and the position of the turning tool are different, which determine the position of the tool nose arc. When performing tool compensation, the direction of the tool automatically deviating from the contour of the part is different. Therefore, the parameters representing the shape and position of the turning tool must also be input into the memory.

(I) Process of tool radius compensation

The tool radius compensation process has three steps.

1. Knife compensation establishment

The tool approaches the workpiece from the starting point. Based on the programmed trajectory, the tool center is shifted to the left (G41) or right (G42) by an offset amount. Processing of parts is not possible.

2. Knife repair

The tool center path and the programmed path always deviate by an offset.

3 Knife compensation undo

The tool is evacuated from the workpiece so that the end point of the tool center track coincides with the end point of the programmed track (such as the starting point). Cannot be processed.

(II) Transfer mode and transition mode of C function tool radius compensation

Transfer form

With the difference of the two lines of the programming track before and after, the corresponding tool center trajectories have different transfer forms. The CNC system has both linear and circular interpolation functions. There are four transfer forms for the programming trajectory of these two linear shapes:

(1) There is a straight line transfer;

(2) Transfer between straight line and arc;

(3) Arc and straight transition;

(4) Transfer of arc and arc. ^[1]

The tool nose arc radius compensation greatly improves the numerical accuracy of the workpiece during the machining of the workpiece by the CNC lathe. Writing programs is simpler and easier, saving a lot of time. Production of workpieces with the same specifications and the use of tool position compensation can save more time, which is particularly important for strengthening competition. Zhuzhou Cemented Carbide Group has been doing a good job in this respect as the leader of China's cutting tool industry. By advancing with the times and introducing the most advanced technology to overcome problems in production, it has increased production efficiency several times. Tool compensation in CNC lathes reduces manpower and material resources and brings great benefits to workshop management. Simplified procedures help the tool to produce workpieces with consistent specifications even when worn. ^[2]