Calculating The Required Clamping Force For A Given Speed - Optimum OPTI turn TU 3008G Operating Manual

4.25.4 Calculating the required clamping force for a given speed

The initial clamping force F
due to actuation of the lathe chuck during shutdown. Under the influence of rpm, the jaw mass
generates an additional centrifugal force. The centrifugal force reduces or increases the initial
clamping force depending on whether gripping takes place from the outside in or from the
inside out. The sum of the initial clamping force F
tive clamping F .
sp
F = F ± F [N]
sp sp0 c
Legend
F Total centrifugal force [ N ]
c
F Effective clamping force [ N ]
sp
F Required static clamping force [ N ]
spmin
F Initial clamping force [ N ]
sp0
F Cutting force [ N ]
spz
m Mass of one top jaw [ kg ]
AB
m Mass of chuck jaw set [ kg ]
B
M Centrifugal force torque [ kgm ]
c
1 Newton (N) = 1 kg m/s²
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 minimum clamping force F
workpiece is released in an unchecked manner.

Do not exceed the calculated RPM.

Do not fall below the necessary minimum clamping force.
GB 3442761
62
is the total force impacting radially on the workpiece via the jaws
sp0
sp0
- for gripping from the outside in
+ for gripping from the inside out
Translation of original instruction
and the centrifugal force F
M Centrifugal force of top jaws in [ kgm ]
cAB
M Centrifugal force of base jaws in [ kgm
cGB
n Rotational speed [ rpm ]
r Center of gravity radius [ mm ]
s
r Center of gravity radius of top jaw
sAB
s Clamping force safety factor
sp
s Safety factor for cutting
z
Σ Max. Clamping force of the chuck [ KN
s
Consequently, the
spmin
, is the effec-
c
Version 1.1.6 - 2021-09-17