The CNC four-axis machining center factory simply aligns on the machine tool, which is easy to check during processing, easy to calculate when programming, and the tool setting error is small. The tool setting point can select a certain point on the part (such as the center of the positioning hole of the part), or a certain point outside the part (such as a certain point on a fixture or a machine tool), but it must be determined with the positioning reference of the part Coordinate contact. The accuracy and precision of the forward tool setting, even if the parts require less precision or the program requirements are not strict, the machining accuracy of the selected tool setting part should be higher than the machining accuracy of other directions. Select the part with large contact surface, simple monitoring, and stable processing process as the tool setting point. The accuracy of tool setting points not only depends on the accuracy of CNC equipment, but also depends on the requirements of parts processing. Manually check the accuracy of tool setting to advance the quality of parts in CNC machining. Especially in batch production, the repetitive accuracy of the tool setting point should be considered. The accuracy can be checked by the coordinate value of the tool setting point relative to the machine origin.