How to choose the tool point to use in the CNC machining process? From what position does the tool start to move to the specified position? So at the beginning of the program execution, the position where the tool starts to move in the workpiece coordinate system must be determined. This position is the starting point of the tool relative to the workpiece when the program is executed. So it is called the program starting point or starting point.
This starting point is generally determined by tool setting, so this point is also called tool setting point. When compiling the program, the position of the tool setting point must be selected correctly. The principle of setting the tool setting point is: to facilitate numerical processing and simplify programming. It is easy to align and check during processing; the processing error caused is small. The tool setting point can be set on the machined part, on the fixture or on the machine tool. In order to improve the machining accuracy of the part, the tool setting point should be set as far as possible on the part's design basis or process base.
In actual operation of the machine tool, the tool position point of the tool can be placed on the tool setting point by manual tool setting operation, that is, the coincidence of the "tool position point" and the "tool setting point". The so-called "tool location point" refers to the positioning datum point of the tool, and the tool location point of the turning tool is the tool tip or the center of the tool tip arc. The flat-bottomed end mill is the intersection of the tool axis and the bottom of the tool; the ball-end mill is the center of the ball, and the drill is the point. Using manual tool setting operation, the tool setting accuracy is low, and the efficiency is low.
