
204 Fundamentals of Machining Processes
Therefore, the minimum pitch, P
Ao
, becomes
P
kSbl
P
A
sz b
o
=
⋅
<
σ
3. The resultant broaching force, F
v
, should be less than the maximum
allowable force by the machine, F
m/c
:
m/
FkSb
m/cszb
PkSb
P
m/cszb
η
4. In order to make sure that 2–3 teeth are in actual contact at a time,
the pitch of broach P should be less than half the workpiece length
(l/2), which ensures better guidance and smoother cutting action.
5. Sometimes a broach tool will vibrate when a heavy cut is taken,
especially when the cutting load is not evenly distributed. Vibration
may also occur when tooth engagement is ir ...