Tool setting in NC milling When the workpiece and tool (or tool setting tool) are installed, the tool setting operation can be carried out according to the following steps. First, set the mode switch to the "Return to Reference Point" position, and press the keys in X, Y and Z directions to return the machine tool to the reference point. At this point, the screen will display the coordinates of the tool setting reference point in the machine coordinate system. If the origin of the machine tool coincides with the reference point, the coordinates will be displayed as (0,0,0). 1) Take the symmetrical center of the blank hole or shape as the tool alignment point (1) Use the centering cone shaft (2) to determine the center of the small hole, and use the dial indicator (3) to find the center of the hole. The electronic edge finder is clamped on the spindle like a common tool, and there is a fixed potential difference between the handle and the contact. When the contact contacts the metal workpiece, a loop current is formed through the lathe bed. Gradually reduce the step increment, so that the contact is in extreme contact with the workpiece surface (further lighting, retrogression, extinction), that is, it is considered to be located on the workpiece surface. 2) Take the intersection of mutually perpendicular reference edges of the blank as the tool alignment position point (1), move the direction keys along the X axis and the Y axis, and move the tool or edge finder above the left (or right) vacancy of the workpiece. Let the tool descend again, and finally adjust and move the X axis so that the circumferential cutting edge of the tool contacts the left side (or right side) of the workpiece, and record the X coordinate x a of the tool in the machine tool coordinate system at this time. Then press the X-axis to move the direction key so that the tool leaves the left (or right) side of the workpiece. (2) Adjust and move to the front (or back) side of the workpiece with the circumferential cutting edge of the tool in the same way, and record the Y coordinate y a of the tool in the machine tool coordinate system at this time. Finally, let the tool leave the front (or back) of the workpiece and pick it up to a position far away from the workpiece. (3) If the diameter of the cutter or edge finder is known as d, the coordinates at the intersection of the reference edges should be (x a +D/2, y a +D/2). 3) Tool Z-direction tool alignment When the tool centers in X and Y directions (that is, the spindle center) are aligned, the tool alignment can be removed and replaced with the benchmark tool for Z-direction tool alignment. The Z-direction tool alignment point is usually based on the upper and lower surfaces of the workpiece, which can be set accurately by using the Z-direction setter, and its principle is the same as that of the edge finder. As shown in Figure 8-5, if the upper surface of the workpiece is the zero point of the workpiece with Z=0 and the standard height of the Z-direction setter is 50, the coordinate of the tool in the workpiece coordinate system should be Z=50 when the indicator light is on because the lower surface of the tool is in contact with the Z-direction setter. Write down the result that the z coordinate value of the tool in the machine tool coordinate system is reduced to 50. 1.