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6 Material removal rate Calculations:
The material removal rate (Q) in
can be calculated by: 1 Machined workpiece diameter

2 The pitch angle

Example

A hollow steel rotary workpiece of diameter
D=250 mm is roughly machined by turnmilling 3 The feed at the axial direction
technique with the use of indexable milling
cutter SOF 8/16-D050-04-22R carrying inserts
ONMU050505-TN-MM IC830.
The workpiece material is low-alloy steel AISI
4340 (~DIN W. Nr. 1.6582, ~JIS SNCM 447), 4 RPM of the workpiece
HB 260…280.

The machining stock is 3 mm.

A planner needs to find cutting data, numerical 5 Velocity of the cutter at the spiral direction
values for CNC programming and metal removal
rates for this operation.

Cutter data
6 Width of cut
Nominal diameter D=50 mm
No. of teeth Z=4

Initial cutting conditions 7 Material removal rate

The planner decided to remove all stock by
one pass and, for ensuring optimal cutting, to
perform milling with width of cut 70% of D.
So, depth of cut ap=3 mm and pitch=35 mm.

Based on ISCAR recommendations, the
planner set cutting speed Vc=170 m/min
(tool rotational velocity nt=1082.3 rpm
accordingly) and feed per tooth at the
spiral direction fz’=0.2 mm/tooth.

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