Tools with ISO elements | Technical appendix | Terminology and formulae milling
Terminology and formulae, milling
Milling cutter diameter
Dc [mm]
κ
A
90°
75°
A
B
Dc
Ra [µm]
ap [mm]
Average roughness depth
Rz [µm]
ae [mm]
Number of cutting edges
z
Spindle speed
n [U/min]
ap
ap
Average roughness
ae
ae
Formulae
Feed per turn
fu
mm
= [ –––– ]
U
fu
= z · fz
Feed per tooth
fz
mm
= [ –––– ]
Zahn
fz
vf
= –––––––––
n·z
fz during face milling:
5 4 32 1
5
1
2
fz
fu
186
4
3
Tools with ISO elements | Technical appendix | Terminology and formulae milling
1
= [ –––– ]
min
vc · 1000
= –––––––––
�·D
Spindle speed
n
Average chip thickness
hm = [ mm ]
Cutting speed
vc
m
= [ –––– ]
min
vc
� · Dc · n
= –––––––––
1000
Feed rate
vf
mm
= [ –––– ]
min
vf
= fz · z · n
Q
cm3
= [ –––– ]
min
Q
= ae · ap · vf
Material removal rate
n
hm = sinκ · fz ·
ae
––––
D
Disc, groove, shoulder milling
fz 0,1
Feed value compensation
If a shoulder with a cutting depth of only 0.5 mm is
machined using a milling cutter ø 40, the feed must be
multiplied with a factor of 5 to arrive at the actual feed
or fz 0.1 (see example below).
1.5
5
10
20
0,0
9
7
0,0
0,04
0,02
The calculated and actual feed can vary depending on
the cutting depth and the milling cutter diameter.
0.5
Machining steps with low radial cutting depth such as
disc milling, groove milling or milling a shoulder require
correction of the feed at the cutting edge as it enters
the workpiece.
Example:
Tool:
z:
fz:
f:
A major advantage of the application of this formula is
the increase in the productivity on the effective usage
of the milling cutter.
Milling cutter ø 40 mm
5
0,1 mm/rev
0.5 mm/rev
Radial cutting depth
[ap]
Feed per tooth
[fz]
Maximum chip thickness
[hmax]
Required vf to obtain fz 0.1
Increase factor
20
10
5
1,5
0,5
0,1
0,1
0,1
0,1
0,1
0,1
0,09
0,07
0,04
0,02
1.000
1.111
1.429
2.500
5.000
1,00
1,11
1,43
2,50
5,00
Based on the above example, the feed per tooth can be increased with a low ap/D ratio or a setting angle < 90°.
187
Technical
appendix
Note: