26 01.00|ROTA THWplus |en
Calculation of the permissible rpm nzul in case of a given initial
clamping force Fsp0
The following formula can be used to calculate the permissible
RPM for a given initial clamping force during shutdown:
The calculated permissible RPM may not exceed the maximum
RPM inscribed on the chuck for safety reasons!
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:
The calculated RPM n
zul
= 1495
rpm
is smaller than the maximum
permissible RPM of the chuck n
max
= 3200
rpm
(see "Chuck data" ta-
ble ( 6.1, Page 19)
).
This calculated RPM may be used.
Grades of Accuracy
Tolerances for run-out accuracy and axial run-out accuracy corre-
spond to the Technical Supply Terms for lathe chucks as per DIN
ISO 3089.
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