6 | Operation
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DURO-A RC
6.2.1
Determining the Clamping Force
The clamping force F
sp
of a power chuck is the sum of all forces which have a
radial effect on the workpiece. The clamping force applied before beginning
material removal with a stationary chuck is F
sp0
. The clamping force F
sp
avail-
able for the material removal process is on the one hand the initial static
clamping force F
sp0
available increased or reduced by the centrifugal force F
c
of the jaws.
[N]
(1)
The clamping force F
sp
available for the material removal process results from
the clamping force F
spz
necessary for the material removal process multiplied
by the safety factor S
z
≥ 1.5, the size of which comprises the accuracy of the
influence parameters such as load, clamping coefficient etc.
[N]
(2)
With the static initial clamping force F
sp0
, a safety factor S
sp
≥ 1.5 is to be
taken into account, so that the static clamping force F
sp0
results in:
[N]
(3)
The (-) sign applies to clamping from the outside in.
The (+) applies to clamping from the inside out.
6.2.2
Determination of the Speed
The formulae (1), (2) and (3) when clamping from the outside in result in:
[N]
(4)
whereby the centrifugal force F
c
depends on the sum of all masses of the jaws
m
B
, the radius of the centre of gravity r
s
and the speed n. This results in the
following formula:
[N]
(5)
The expression m
B
· r
s
is referred to as the centrifugal force M
c
.
[mkg]
(6)
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