If the tool marks of the live plane milled out are in the shape of arcs, then the middle of the live plane must be concave, but the large cutter head you use has a large diameter and a narrow live surface, so the phenomenon of concave is not obvious.
The diameter of the small cutter head is small, so the depression is more obvious. If you tilt the angle of the spindle of the milling machine to a large angle, such as tilting to the horizontal. At this time, when the main shaft of the milling machine is completely parallel to the work surface, the live plane milled by the milling machine will form an arc R equal to the radius of the milling cutter head.
As the spindle of the milling machine is gradually raised, the radius of the concave arc will become larger and larger, and the work will become more and more flat. If the milling plane is to be completely flat, the milled tool marks should be intersecting tool marks. This is just like vertical flat grinding. When the machine tool is adjusted to have a cross pattern, it is really the main shaft of the machine tool that is perpendicular to the work surface of the machine tool.
The same is true for the milling machine. When the cross pattern can be milled, the main shaft of the milling machine is truly perpendicular to the working table of the milling machine. At this time, there will be no concave phenomenon in the milled work. Now this phenomenon occurs, indicating that the spindle of your milling machine is not perpendicular to the work surface. To adjust the verticality of the main axis.
In addition, whether the work you are processing is a sheet material, due to the characteristics of the machine flat-nose pliers, when clamping a sheet that is not too thick and milling the plane, the work can only be clamped on the upper part of the jaws, the jaws will arch upwards, and the clamping is too high. If it is tight, the sheet will be deformed, such as bulging. When the support of the pliers is released after milling, the flat-milled sheet will sag in the middle.
Therefore, when milling a sheet that is not too thick, do not clamp it too tightly to prevent the workpiece from being clamped and deformed, and the milled work will appear concave.
Of course, there are other possible reasons, such as the workpiece is hollow, elastic, the tool is not fast, there is no compression, the allowance is too large, the mechanism is not straight, etc. In short, the problem must be found in order to effectively solve the problem.
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