SCHUNK ROTA THW3, Assembly And Operating Manual

Page: 21 / 56

Technical data
DANGER
Risk to life and limb of the operating personnel and significant
property damage when the RPM limit is exceeded!
With gripping from the outside inwards, and with increasing
RPM, the effective clamping force is reduced by the magnitude
of the increasing centrifugal force (the forces are opposed).
When the RPM limit is exceeded, the clamping force drops
below the required minimum clamping force F
spmin
.
Consequently, the workpiece is released spontaneously.
•
Do not exceed the calculated RPM.
•
Do not fall below the necessary minimum clamping force.
The workpiece
will be
uncontrollably
released in
this area
Speed of rotation
Clamping force
Centrifugal
force
Effective clamping force
Minimum required clamping force
Initial clamping force during shutdown
Reduction in effective clamping force by the magnitude of the total centrifugal force, for gripping from the outside
inwards.
The required effective clamping force for machining F
sp
is
calculated from the product of the machining force F
spZ
and the
safety factor S
z
.
This factor takes into account uncertainties in the calculation of
the machining force. According to VDI 3106:
S
z
≥ 1.5.
From this we can derive the calculation of the initial clamping
force during shutdown:
(+) for gripping from the outside inwards
(–) for gripping from the inside outwards
21 06.00 | ROTA THW3 | Power Chuck | en | 1440828