Some parts have flat bottoms in the inner holes and need to be turned.
An example is used here to introduce the CNC lathe processing method of the flat bottom of the inner hole of the workpiece.
Figure 1 is a part diagram of a part named "SB end cap".
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The material of this part is ductile iron, the roughness of the bottom surface of the inner hole is not high, and the dimensional accuracy between the bottom surface and the large end surface is not high.
Introduce the first method of turning the flat bottom surface first (see Figure 2).
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This is an outer circle turning tool with a 35º equilateral blade that is clamped horizontally. First pass the center turning to the center of the circle (spindle reversal), and then pass the center (conventional) turning to the large diameter (spindle reversal) ).
Note that the main shaft should be stopped during the intermediate transition.
The blade must be single sided (because it has a 5º relief angle).
This method is suitable for the larger bottom surface of the car. This kind of cylindrical turning tool and blade companies generally have it, so it can be used first when turning a large bottom surface.
Then introduce the second method of the bottom surface of the car (see Figure 3).
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This is to use an inner circle turning tool as shown in the figure, first pass the center to the center of the circle (spindle reverse), and then pass the center (conventional) to the large diameter (spindle reverse). This kind of inner circle turning tool has poor rigidity and is only suitable for finishing turning with a small amount of removal. This kind of turning tool companies generally do not have it, but they can be purchased specially when processing large quantities of workpieces.
Finally, introduce the third method of the bottom surface of the car (see Figure 4).
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This is done with a keyway milling cutter and an internal turning tool.
If the lathe has a tailstock, the keyway milling cutter can be mounted on the tailstock through the drill chuck.
If it is a multi-station horizontal tool holder, the keyway milling cutter can be installed in the inner circular tool holder, and the X-direction tool setting must be very accurate at this time.
If it is a square tool holder, the keyway milling cutter should pass through a transition tool holder and then be installed into the clamping groove of the square tool holder. At this time, the center height must be well spaced, and the X-direction tool setting must also be very accurate.
