Tips on tool setting for side milling heads of gantry machining centers

A gantry machining center refers to a machining center in which the Z-axis of the spindle is set perpendicularly to the workbench. The overall structure is a large scale cnc machining center with a portal structure frame composed of double columns and a top beam. There is a crossbeam in the middle of the double columns. It is especially suitable for processing large workpieces and workpieces with complex shapes.

Tool setting, simply put, is to determine the position of the program point in the machine tool coordinate system so that the tool setting point coincides with the tool position point. In the milling process, the tool setter plays a key role. So do you know what are the tips for tool setting of the side milling head of the gantry machining center? Let’s take a look~

In milling processing, in order to facilitate the adjustment of the relative position of the tool and the fixture, a tool setting block is usually installed on the fixture. Sit on the base of the jig. The position of the tool can be checked between the tool setting block and the tool using a plug piece. The general thickness of the plug is m=1.3 and 5 cm. The latter size is more widely used, and its thickness tolerances are matched with Level 2 accuracy.

There are 40 spiral grooves with a spiral angle of 30° on the circumference of the moving roller, and the cross-sectional shape of each groove is a right triangle. After completing other processes, it is necessary to use a right-angle milling head on the gantry online machining service and cnc  center, rotate it 30° counterclockwise, and then mill the spiral groove. According to the particularity of the groove structure and the number of grooves, it was decided to use a three-sided edge forming milling cutter for forming processing. Since there are multiple rollers of the same type, manual programming and macro programs are used.

Since the working state of the right-angle milling head must be that the cutter axis is perpendicular to the spiral groove, that is to say, the cutterhead end line (in the projected diameter line of the cutterhead on the X-Y plane) must be in the same direction as the spiral groove.

Then with the movement of the workbench, the rotation of the A-axis of the machine tool and the rotation of the cutter axis, under the control of the program, the spiral groove can be machined. But the premise is to find out the position of the programming zero point in the machine tool coordinate system under working conditions. Only by finding out the position of the programmed zero point can the program control the accurate movements of each axis and process the workpiece.

​Finally, install a standard tool bar in the right-angle head, and then rotate it 30° counterclockwise along the Y-axis. The knife rod is tangent to the standard rod. At this time, the distance between the tangent point of the knife rod and the standard rod and the center of the standard rod is d/2. Lift the tool bar and translate it by d/2. In fact, the workbench is translated by d/2 in the negative direction of X. At this time, the position of the center line of the tool bar is the position of the knife axis.

Lock the X and Y, lift the Z axis, remove the tool bar, replace it with a three-sided edge milling cutter, and adjust the Z axis so that the gantry machining centers position point coincides with the center point of the standard rod end face, as shown in the top view in Figure 2. In the G54 coordinates, move the distances of X(L+h-d/2) and Y(D/2+b-d/2) respectively, and then clear them. That is, when the right-angle milling head is rotated 30°, use the three-sided milling cutter for processing. Programmed zero point of the spiral groove.