In CNC machining, flat-end mills are commonly used for milling the inner and outer contours of planar parts and for milling planes. Empirical data regarding the relevant parameters of this tool are as follows: First, the milling cutter radius RD should be less than the minimum radius of curvature Rmin of the inner contour surface of the part, generally taken as RD = (0.8-0.9)Rmin. Second, the machining height H of the part should be less than (1/4-1/6)RD to ensure sufficient tool rigidity. Third, when milling the bottom of an inner groove with a flat-end mill, since the two passes at the bottom of the groove need to overlap, and the effective radius of the tool's bottom edge Re = R - r, i.e., the diameter d = 2Re = 2(R - r), the tool radius is taken as Re = 0.95 (Rr) during programming. For machining some three-dimensional surfaces and contours with varying angles, ball end mills, ring end mills, drum end mills, tapered end mills, and disc end mills are commonly used.
Most CNC machine tools use serialized and standardized cutting tools. There are national standards and serialized models for tool holders and tool heads of indexable external turning tools, face turning tools, etc. For machining centers and machine tools with automatic tool changers, there are already serialized and standardized regulations for tool holders. For example, the standard code for tapered shank tool system is TSG-JT, and the standard code for straight shank tool system is DSG-JZ. In addition, before using the selected tool, the tool size must be strictly measured to obtain accurate data. The operator then inputs this data into the data system, and the program calls it to complete the machining process, thereby producing qualified workpieces.