When the milling cutter is used, it should be noted that the cutting speed near the center is very small, close to "zero", so the cutting conditions are relatively harsh. Therefore, if possible, the axis of the milling cutter should be tilted from the normal direction of the workpiece. According to the test, when this Angle is about 15°, the life of the tool will reach a maximum value.
The overhang of the tool will have some influence on the tool life in high-speed machining. According to the results of limited tests, when the overhang of the 6mm end mill is increased from 30mm to 60mm, the tool life is expected to increase to 140% to 230% of the original.
In copying machining, the milling method along the cross-section profile (also known as contour milling) is superior to the milling method along the longitudinal cross-section profile (also known as climbing milling). Because the cutting conditions of contour milling are more consistent, the cutting is smooth, the surface roughness of the workpiece is also better, and the cutting conditions of slope milling are extremely unstable, the tool is very easy to break the edge near the center, and the surface roughness of the workpiece is not ideal. In the case of uphill milling, the experiment shows that the tool life of up-milling is better than that of up-milling, and the tool life of up-milling is better than that of down-milling.
The change of cutting force when milling the internal cavity, in the milling of the internal cavity, when the tool is fed to the corner, due to the sudden increase of the cutting envelope Angle, its radial force will increase sharply, and the peak will reach about 170% of the normal cutting value. Therefore, we recommend the implementation of the so-called "cycloidal cutting" at the corner, so that the sudden increase in the cutting force can be avoided, so as to achieve smooth cutting and extend the life of the tool.
We should pay special attention to cooling. Oil mist cooling (also known as quasi-dry cutting) is more ideal, jet cooling, high pressure and large flow internal cooling can also be accepted, but low pressure, external cooling should be avoided.
