Calculating The Clamping Force And Speed Of Rotation - Rohm KFD-HE Instrucciones De Servicio

7. Calculating the clamping force and speed of rotation

7.1 Determing the clamping force
The clamping force F
all jaw forces acting radially on the workpiece. The
clamping force applied before the cutting process and
with the chuck stationary is the initial clamping force
F . The clamping force F
spo
process is, firstly, the initial clamping force F
with the chuck stationary. This force is then increased or
decreased by the centrifugal force F
F = F  F
sp spo c
The (--) sign is for clamping forces applied from the
outside in.
The (+) sign is for clamping forces applied from the
inside out.
The clamping force F
process multiplied by safety factor S
7.2 Determining the permitted speed of rotation
7.2.1 Centrifugal force F
Formulae (1), (2) and (3) produce the following result
for clamping from the outside in:
F
spo
F =
sp
S
sp
In this case the centrifugal force F
the mass of all jaws m
and the speed of rotation n.
The following formula can be derived:
. .
F = (m r ) (
c B s
The expression m
B
moment M
c
.
M = m r
c B s
7.3 Permitted speed of rotation
The following formula applies for determining the
permitted speed of rotation for a specific machi-
ning job:

30
n =
π
perm
(Note the number of jaws for Σ M
C
B
R
L
A
A
of a rotary chuck is the total of
sp
avialable during the cutting
sp
spo
on the jaws.
c
[N]
avialable during the cutting
sp
1,5.
²
z
, and centrifugal moment M
c
-- F [N]
c
is dependent on
c
, the centre of gravity radius r
B
.
n
2
π
) [N]
30
⋅
r is called the centrifugal
s
[mkg]
.
F -- (F S
spo spz z)
[min

M
c
(9)
)
c.
Chuck size
r
s
Max. weight in kg
R max. in mm
a
L max. in mm
a
Centrifugal moment M
The size of this factor is determined by the accuracy of
the influence parameters such as loading, clamping
coefficient, etc.
F = F
sp
A safety factor of S
existing
consideration for the static initial clamping force F
Consequently, the following applies for the clamping
force with the chuck stationary.
(1)
F = S
spo
The (--) sign is for clamping forces applied from the
outside in.
The (+) sign is for clamping forces applied from the
inside out.
The following formula applies to chucks with sliding
c
and false jaws in which the false jaws AB can be mo-
ved in order to alter the clamping area and the sliding
jaws GB approximately maintain their radial position:
M = M
c
(4)
M
cGB can be obtained from the table below.
M
cAB can be calculated using the following formula:
s
M = m
cAB
(5)
The clamping forces can be obtained by referring to
the clamping force/speed of rotation diagram (see
page 28) when using standard series production
jaws allocated to specific chuck by the chuck
manufacturer.
(6)
Do not exceed the maximum speed of rotation
n of the chuck (marked on the body of the
max
--1
chuck). This applies even if the calculated
]
permitted speed of rotation n
the maximum speed n
130 170
A 54 66,7
B 23 36,5
C 29
0,22 0,7
39
18
0,015 0,030
GB [mkg]
C
.
S [N]
spz z
1,5 should be taken into
²
p
.
(F  F ) [N]
sp sp c
+ M [mkg]
cGB cAB
⋅
r [mkg]
AB sAB
Important:
is greater than
perm
.
max
210 254
75 95
36,5 45
53 53 54,5
0,88 1,4
52 68 80
29 29 30
0,051 0,125
(2)
.
spo
(3)
(7)
(8)
315 400
95
45
54,5
1,4
110
30
0,300