When the precision CNC machining custom accuracy requirements are not high, you can directly use some surfaces in the workpiece or fixture as the tool surface; when the machining accuracy is high, the tool point should be selected as far as possible on the design standard or process standard of the part. For example, for parts requiring hole positioning, the pivot of the hole is more suitable for the tool point. The tool point must have some coordinates related to the positioning reference of the workpiece, how to determine the relationship between the machine tool standard system and the workpiece coordinate system. The selection of the tooling point should facilitate the calculation of coordinate values and make it convenient for tool setting. When tool setting, the tooling point should be made to overlap with the tooling point. The so-called tool position point, for the thick-bottomed end mill, is the intersection of the bottom edge of the tool; ball end mill is the ball center of the ball head; turning tool is the tip of the tool; drill is the tip of the drill; wire level cutting machine tool is the focus of the wire level pivot and the surface of the part. Axis CNC machining situation requires a tool change, should require a tool change point, the location of the tool change point should be based on the principle that the tool change shall not knock the workpiece, fixture and its machine tool and set.
