Rpm; Rpm (Surface Velocity) - Dukane SVB031 User Manual

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...
π D RPM
v =
60
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
800
600
400
200
v
0
1
D
Figure 5–2 Dependence of the Surface Velocity on the Weld Diameter at various RPMs
Dukane Manual Part Number 403-547-03
2 3 4
Average Weld Diameter (inch)
6 8
Section 5 – Theory of Operation
10 12
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