Optimum BF20 Vario - Speed Settings and Calculations

Operation
OPTIMUM
MASCHINEN - GERMANY
© 2010
GB
Page 30 Drilling-Milling machine BF 20 Vario ; BF 20 L Vario Version 3.1.4 9 / 03 / 2010
4.8 Selecting the speed
For milling operations, the essential factor is the selection of the correct speed. The speed
determines the cutting speed of the cutting edges which cut the material. By selecting the cor-
rect cutting speed, the service life of the tool is increased and the working result is optimised.
The optimum cutting speed mainly depends on the material and on the material of the tool. With
tools (milling cutters) made of hard metal or ceramic insert it is possible to work at higher speeds
than with tools made of high-alloyed high-speed steel (HSS). You will achieve the correct cut-
ting speed by selecting the correct speed.
In order to determine the correct cutting speed for your tool and for the material to be cut, you
may refer to the following standard values or a table reference book (e.g. Tabellenbuch Metall,
Europa Lehrmittel, ISBN 3808517220).
The required speed is calculated as follows:
n = speed in min
-1
(revolutions per minute)
V = cutting speed in m/min (meters per minute)
d = tool diameter in m (meters)
4.8.1 Standards values for cutting speeds
[ m/min ] with high-speed steel and hard metal at conventional milling
The results are the following standard values for speeds depending on the milling cutter diame-
ter, cutter type and material.
n
V
π d×
------------
=
Tool Steel Grey cast iron
Age-
hardened
Al alloy
Peripheral and side milling cutters
[ m/min ]
10 - 25 10 - 22 150 - 350
Relieved form cutters [ m/min ] 15 - 24 10 - 20 150 - 250
Inserted tooth cutter with SS [ m/min ] 15 - 30 12 - 25 200 - 300
inserted tooth cutter with HM [ m/min ] 100 - 200 30 - 100 300 - 400
Tool diameter
[ mm ] peripheral and side milling
cutters
Steel
10 - 25 m/min
Grey cast iron
10 - 22 m/min
Age-
hardened
Al alloy 150 -
350
m/min
Speed [ min
-1
]
35 91 - 227 91 - 200 1365 - 3185
40 80 - 199 80 - 175 1195 - 2790
45 71 - 177 71 - 156 1062 - 2470
50 64 - 159 64 - 140 955 - 2230
55 58 - 145 58 - 127 870 - 2027
60 53 - 133 53 - 117 795 - 1860