The main goal of roughing die roughing is to pursue the material removal rate per unit time and prepare the geometric outline of the workpiece for semi-finishing. In the process of cutting, the change of the metal area of the cutting layer leads to the change of the load on the tool, which makes the cutting process unstable, the tool wear speed uneven and the quality of the machined surface decline. Many CAM softwares developed can keep the cutting conditions unchanged by the following measures, thus obtaining good machining quality. Constant cutting load. Through calculation, a constant cutting layer area and material removal rate can be obtained, thus balancing cutting load and tool wear rate and improving tool life and machining quality. Avoid sudden change of tool feed direction. Avoid burying tools in the workpiece. For example, when machining the mold cavity, the tool should not be inserted vertically into the workpiece, but should be inclined downward (usually the inclination angle is 2 ~ 3), and it is best to use spiral cutting to reduce the tool load; When machining the die core, try to cut the tool from the outside of the workpiece, and then cut it horizontally. When cutting and cutting the workpiece, the tool should be inclined (or curved) to avoid vertical cutting and cutting. Climbing cutting can reduce cutting heat, reduce tool stress and work hardening degree, and improve machining quality. The main goal of semi-finishing die semi-finishing is to make the contour shape of workpiece smooth and the surface finishing allowance uniform, which is especially important for tool steel die, because it will affect the change of cutting layer area and tool load during finishing, thus affecting the stability of cutting process and the quality of finished surface. Rough machining is based on volume model and finish machining is based on surface model. However, the geometric description of parts in the previously developed CAD/CAM system is discontinuous. Because there is no intermediate information describing the machining model after rough machining and before finishing, the distribution and maximum residual machining allowance of the blank surface are unknown. Therefore, the semi-finishing strategy should be optimized to ensure the uniform residual machining allowance on the workpiece surface after semi-finishing.