The depth of cut of solid end mills needs to be set appropriately according to the machining method, workpiece material and cutting edge geometry.
The depth of cut is set at values found by multiplying the diameter or ball nose radius by a fixed coefficient. The image to the right shows a depth of cut standard for 2-flute, square corner, coated carbide end mill. If the workpiece materials are harder, the depth of cut should be decreased.
Number of flutes
When the number of flutes increases, the depth of cut needs to be decreased. The image to the right shows an example of a 6-flute end mill.
Roughing end mills
Standard depths of cuts for roughing end mills can be set at a larger value than ordinary type end mills. This is because the cutting resistance is reduced because the chips are broken into short lengths by the wavy cutting edges. Also for the same reason, the depth of cut for semi-finishing end mills can be increased.
The image is showing that the ordinary cutting edge ae= 0.05~0.2D1, whereas for the semi-finishing cutting edge with the nicks can be used with ae= 0.5D1. The nicks in the cutting edge ensure that the chips are finely broken up leading to lower cutting resistance.
Example of a carbide roughing edge end mill (VC-SFPR). Generally when selecting a roughing edge end mill HSS is selected.
Ball nose end mill
Also for ball nose end mills, when the workpiece materials are harder the depth of cut needs to be decreased.
When machining at a larger depth of cut than standard, machining can be possible if the feed rate is decreased.
The IMPACT miracle series can be used to machine up to 70 HRC.
The image shows the depth of cut when carrying out slotting.
For the ordinary cutting edge type ap= 0.05~0.2D1.
For the semi-finish and roughing cutting edge type ap= up to 1D.