Version 1.0 - 2020-12-22
115
Translation of original instruction
3440287
│
3442710
│
3442712
GB
K11-
80-10
0-12
5_I
SO-
702-
4_344
0287
_344
2710
_344
2712_
ba-i
nte
grat
ed_
GB.
fm
3.11.8 Clamping jaw centrifugal force
To calculate the required tensioning force for processing a workpiece, the centrifugal force of
the clamping jaws must be taken into account.
The permissible speeds can be determined in accordance with VDI Guideline 3106 "Determin-
ing the permissible speed for lathe chucks (jaw chucks). This guideline also allows for the resid-
ual tensioning force at a specified speed to be determined.
The required effective clamping force for machining F
sp
is calculated from the product of the
machining force F
spz
with the safety factor S
z
. This factor takes into account uncertainties in the
calculation of the clamping force.
According to VDI 3106, the following also applies here:
From this we can derive the calculation of the initial clamping force during shutdown:
ATTENTION!
This calculated force must not be larger than the maximum clamping force
∑
S
engraved
on the chuck.
From the above formula it is evident that the sum of the effective clamping force F
sp
and the
total centrifugal force F
c
is multiplied by the safety factor for the clamping force S
sp
.
According to VDI 3106, the following also applies here:
The total centrifugal force F
c
is dependent both on the sum of the masses of all jaws and on the
center of gravity radius and the RPM.
Fc
Centrifugal force in N
m
Mass in kg/set
rs
Centre of gravity distance to the centre of the chuck in
metres
n
Speed min
-1
r
0
Centre of gravity distance to the clamping jaw
Base tensioning force
Required minimum tensioning force
Clamping force
Centrifugal for
ce
Speed
Ef
fecti
ve
tensioning force
Workpiece is
released uncontrollably
F
sp
= F
spz
·
S
z
[ N ]
F
sp0
= S
sp
·
(F
sp
± F
c
) [ N ]
- for gripping from the outside in
+ for gripping from the inside out
S
sp
≥
1.5
