Torques per screw
01.00|1416054_ROTA-M2 + 2 |en
27
The total centrifugal force can now be calculated:
Initial clamping force during shutdown that was sought:
Calculation of the permissible speed in case of a given initial
clamping force
Calculation of the permissible RPM n
perm
in case of a given initial
clamping force F
sp0
The following formula can be used to calculate the permissible
RPM for a given initial clamping force during shutdown:
CAUTION
For safety reasons, the calculated permissible RPM may not
exceed the maximum RPM inscribed on the lathe chuck!
Example of calculation: Permissible RPM for a given effective
clamping force
The following data is known from previous calculations:
• Initial clamping force during shutdown F
sp0
= 17723 N
• Machining force for machining job F
spz
3000 N (application-
specific)
• Total centrifugal torque of all jaws ∑M
c
= 2,668 kgm
• Safety factor S
z
= 1.5 (according to VDI 3106)
• Safety factor S
sp
= 1.5 (according to VDI 3106)
NOTE:
Masses of the jaw mounting screws and T-nuts are not taken into
account.
Identifying the permissible RPM:
3.4.3
