Basic Safety Instructions; Optional Soft Lathe Chuck Jaws; Calculating The Required Clamping Force For A Given Speed - Optimum Optiturn TU 2807VB Betriebsanleitung

4.23.2 Basic safety instructions

The permissible speed (as per VDI 3106) must be calculated for the machining allowance;

the maximum guide speed must not be exceeded. The calculated values must be tested by
performing a dynamic measurement.
The max. guide speed may only be applied with max. introduced actuation force and a

chuck that is perfect working condition.
If the chuck is involved in a collision, it must be subjected to a crack test before using it

again. Damaged parts must be replaced using original spare parts.
The chuck may only be mounted and removed, commissoned, operated and maintained by

authorised and skilled staff following safety training.
We recommend checking the clamping force before starting a new series batch and

between maintenance intervals with a clamping force measuring device. Only regular
checks guarantee best possible safety.

4.23.3 Optional soft lathe chuck jaws

CAUTION!
The optionally available soft chucks jaws are jaws, which must be stepped according to
the application. Unstepped jaws lead to an increased centrifugal torque with a reduced
permissible rotational speed of the rotary chuck.

4.23.4 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
GB
3440287│3442710│3442712
142
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
, is the effec-
c
Version 1.0 - 2020-12-22