Spin Welder User’s Manual
Section 5 – Theory of Operation
Page 31
Page 30
Dukane Manual Part Number 403-547-03
Dukane Manual Part Number 403-547-03
RPM (Surface Velocity)
Maximum weld strength occurs at an optimum pres-
sure and speed. Higher rotation speeds decrease the
weld initiation time, but to a lesser extent than axial
pressure. This means that you will typically need to
make larger percentage changes in motor speed to
see a noticeable difference in the weld properties
than you would in axial pressure. The basic expres-
sion commonly seen is:
v = πDN
where
v
is surface velocity (inch/sec)
π
= 3.14
D
= average diameter of the joint (inch)
N
= angular velocity (rev/sec)
but
N = RPM/60
so we can write…
v =
The initial target for
v
is in the 360 to 600 inch/sec
range. This corresponds to the common quoted val-
ues of 30 to 50 ft/sec. Surface velocities as low as
Figure 5–2
Dependence of the Surface Velocity on the Weld Diameter at various RPMs
400
600
800
0
200
1
2
4
6
8
10
12
3
v
Average Weld Diameter (inch)
D
Surface Velocity (inch/sec)
3500 RPM
N =
58.3
500 RPM
N = 8.3
1000 RP
M
N = 16.7
1500 RPM
N =
25.
0
2500 RPM
N = 41.7
π D RPM
60
