Tools with ISO elements | Technical appendix | Circular milling
Circular milling
Circular milling with two-axis feed rate
Feed rate at the
cutting edge
(at the contour)
Feed rate at the
centre of the tool
(at tool centre)
vf [mm/min]
Vf
d
D
Circular milling internal machining
d
D
Circular milling external machining
vfm [mm/min]
Vfm
Vf
D+d
vfm = vf ––––––
D
Vfm
D–d
vfm = vf ––––––
D
Moving in and out
On moving in or out the contour should always be approached or
left over a quarter or semi-circle. This action will ensure tangential
plunging or removal of the tool from the workpiece.
In this way dwell marks on the workpiece are avoided and better
circularity of the part machined achieved.

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Tools with ISO elements | Technical appendix | Circular milling
Two axis angled entry – linear (flute)
Inner cutting edge
(trailing)
α
Peripheral cutting edge Face cutting edge
a
b
Ramp angle α:
The maximum plunge angle α is dependent on the tool.
In case of two-axis angled entry various machining
processes take place at the same time:
a) Machining at the entire periphery of the tool
(peripheral machining) with leading indexable insert
b) Machining at the face of the milling cutter with leading insert
c) Machining at the face of the milling cutter with trailing insert
Application notes
For end milling cutter ICM90-B2-Shank
Plunge milling
α
Vertical milling
Modified milling cutter type M
ICM90-B2-Shank, ICM90-B2, ISM90-B2-Shank, ISM90-B2.
If indexable inserts with a radius >1.2 mm are used, the tool body
must be reworded at the peripheral edge as per the table shown.
In this case the modified milling cutter type M can be selected
(see section Milling pages 49-53)
Alternatively the standard milling cutter can also be ordered and
re-worked by the customer.
Standard
Re-worked
ae
Milling cutter
diameter
ø 16, ø 18
ø 20
ø 22, ø 25
ø 28, ø 32
ø 40
ø 25
ø 32
ø 40
ø 50 or more
Indexable insert that
can be used
Milling cutter
diameter
Indexable insert that
can be used
Max. cutting
width ae
ø 16
Type BDMT11T3
Type BDGT11T3
1,5 mm
ø 20 - ø 40
Type BDMT11T3
Type BDGT11T3
5 mm
ø 25 - ø 40
Type BDMT1704
Type BDGT1704
8 mm
Indexable insert that
can be used
Maximum ramp
angle α
Type BDMT11T3
Type BDGT11T3
Type BDMT1704
Type BDGT1704
For shoulder cutter head ICM90-B2
Plunge milling
Milling cutter
diameter
ø 40
α
2,5°
Type BDMT1704
Type BDGT1704
ø 50 or more
Vertical milling
Indexable insert radius
2,0
3,1
4,0
Radius required on the tool body
1,0
1,6
2,5
Maximum ramp
angle α
3°
5°
2,5°
1,5°
0,7°
8°
5°
2,5°
Not recommended
Not recommended
Milling cutter
diameter
Indexable insert that
can be used
Maximum cutting
width ae
ø 25 - ø 40
Type BDMT1704
Type BDGT1704
8 mm
ae
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Technical
appendix
c
Tools with ISO elements | Technical appendix | Helix milling
Helix milling
Helical angled entry
Helical angled entry is an alternative to drilling.
During this process a circular movement is made with
simultaneous axial feed.
Pitch (P):
The pitch (P) corresponds to the axial material removal
rate per revolution.
This aspect is dependent on the workpiece, tool length,
material and machine.
Advantages compare to circular milling
P
Application note
• Bettercircularityandconcentricity
• Bettercuttingbehaviouronapplicationssusceptibletovibration
• Constantangledentryintotheworkpiece
• Themillingcutteriscontinuouslyengaged,noenteringor
exiting per revolution compared to circular milling
α°
Tool ø
Max. possible
plunge
angle α°
80
100
125
140
160
4,3
3,4
2,8
2,4
2,1
Selection of the milling cutter diameter as a function of the size of the bore
In the case of centre-cutting milling cutters
it is important to select the correct ratio of
milling cutter diameter and bore diameter.
The insert must cut along the centre axis.
1
If the milling cutter diameter is too small,
there is a core in the centre.
If the milling cutter diameter is too large,
the centre is not machined. As a result a
protrusion is left. This protrusion presses
the milling cutter axially. There is a collision
between the workpiece and tool.

2
1 Drilling into the solid (flat bottom of the bore)
Milling cutter diameter (mm)
Bore diameter (mm)
80
142-160
100
182-200
125
232-250
140
262-280
160
302-320
Note:
In the case of a bore diameter between the ranges stated, for example 170 mm, the smaller milling cutter with a
diameter of 80 mm is selected. Two machining steps are then necessary to machine the bore.
2 Enlarging a bore (no face machining)
Milling cutter diameter = < 0.5 x bore diameter
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