Torques per screw
22
02.00|ROTA NCA |en
Clamping force/RPM graph for ROTA NCA 330-104
Calculations for clamping force and speed
Missing information or specifications can be requested from the
manufacturer.
Legend
F
c
Total centrifugal force [N]
M
cAB
Centrifugal torque of top jaws [Kgm]
F
sp
Effective clamping force [N]
M
cGB
Centrifugal torque of base jaws [Kgm]
F
spmin
Minimum required clamping force
[N]
n
Speed [rpm]
F
sp0
Initial clamping force [N]
r
s
Center of gravity radius [m]
F
spz
Cutting force [N]
r
sAB
Center of gravity radius of top jaw [m]
m
AB
Mass of one top jaw [kg]
s
sp
Safety factor for clamping force
m
B
Mass of chuck jaw set [kg]
s
z
Safety factor for machining
M
c
Centrifugal force torque [Kgm]
Σ
s
Max. clamping force of chuck [N]
Calculation of the required clamping force in case of a given rpm
The
initial clamping force F
sp0
is the total force impacting radially
on the workpiece via the jaws due to actuation of the lathe chuck
during shutdown. Under the influence of rotation, the jaw mass
generates an additional centrifugal force. The centrifugal force
reduces or increases the initial clamping force depending on
whether gripping is from the outside inwards or from the inside
outwards.
The sum of the initial clamping force
F
sp0
and the
total centrifugal
force F
c
is
the effective clamping force F
sp
.
3.3
3.3.1
