
164 Fundamentals of Machining Processes
The maximum cutting force F
vx
is achieved when the total motor power N
m
is utilized in the machining process. Therefore,
F
vx
3
m
60 10
=
×ηN
m
N
Feed rates and rotational speeds should consequently be selected such that
F
v
is less than F
vx
.
For a given feed rate S, the maximum possible depth of cut, t
x
, becomes
t
N
x
3
mm
60 10
=
×η
mm
The rate of material removal (VRR) in mm
3
/min is given by
=
VSt
where V is the cutting speed in m/min, which for the shaper machine with a
rocker arm mechanism, is measured at the middle of the stroke; it is given by
VNH
r
=+
−
10 1
1
3
s
s
m/min
where
H
s
is the length of ...