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
penetration has been achieved, we want to stop
the rotation as quickly as possible. Too long of a
deceleration time will allow the polymer to solidify
and subsequently shear reducing the weld strength.
Higher axial pressure may help stop the rotation
sooner on large diameter parts.
Hold Time
During Phase V, a holding time allows the plastic
to solidify before removing pressure from the joint.
Larger weld joints take longer for the plastic to
solidify due to the larger mass and poor thermal
conductivity of plastic.
Initial Settings
The following information is presented for infor-
mational purposes only and is in no way meant to
serve as a rule or formula. The information is col-
lected from publicly available books and papers. It is
presented here to provide customers with a general
guideline for setting the initial parameters.
Axial Pressure
This is the most difficult parameter to estimate.
You will require less pressure with an electric mo-
tor spin welder than with an inertial welder due to
the inertial welder’s loss of kinetic energy. A rough
estimate can be derived from a specific pressure of
1.7 MPa (1.7x10
6
Nt–m
-2
) of projected joint area.
This translates to roughly 250 pounds per inch
2
of
weld surface area (total wetted surface area). The
spin welder uses a 3” diameter air cylinder to supply
pressure and it has a boost factor of 7x, so a pres-
sure reading on the regulator of 35 psi translates to
250 pounds of force. Again remember that the 250
pounds per inch
2
of weld surface area is only a start-
ing estimate and differs from values used in inertial
spin welders. Depending upon the joint design, your
application may require 2x more or 0.5x less pres-
sure. Axial pressure typically also has a larger effect
on the weld initiation process than the RPM setting.
TIP
Change only one parameter at a time.
Record your settings. This will make it
easier to arrive at correct settings, un-
til you become familiar with the Spin
Welder.
