© 2016 Nelson Stud Welding, Inc.
Page 17
All Rights Reserved.
January 2016
Part No. 729-110-043 Rev. 1.02
Weld Issue
Weld Parameter Adjustments
Cold Weld
Weld failure at low value, no weld
flash or splatter, and weld base is
incompletely melted (very weak
weld). This indicates that not enough
heat was available.
Weld heat may be increased by:
Reducing spring pressure - Reducing the drop speed and provides
a longer weld time.
Increasing voltage - Increasing the voltage increases overall
energy into the weld.
Check stud ignition tips (possibly too short).
Hot Weld
Weld failure at low value, excessive
weld flash and splatter, and weld base
may be undercut (weak weld). This
indicates that too much heat was
available.
Weld heat may be decreased by:
Increasing spring pressure - Speeding up the weld time and
extinguishes the arc sooner.
Decreasing voltage - Reducing the voltage reduces overall energy
into the weld.
Check stud ignition tips (possibly too long).
Late or Cold Plunge
Cold plunge occurs when the stud
contacts the base material after
solidification of the molten weld metal
has started. This results in
inconsistent weld strength and is
recognized by a shiny, mirror-like
appearance in the fracture surface.
This issue can be rectified by:
Increasing spring pressure - Increasing drop speed and gets the
stud into the molten pool faster.
Decreasing voltage - Reducing the voltage reduces overall energy
into the weld.
Make certain that combo cable is installed (contact mode only).
Otherwise (if gap mode), remove combo cable - Reducing the
amount of weld energy flowing especially in gap mode because of
the high current spike.
Misfire
No arc initiation due to tip failing to
flash.
This issue can be rectified by:
Increasing voltage.
Using 10% detergent solution spray mist.
Problem: Cold Weld
Possible Causes
Possible Solutions
Coiled weld or ground cables. This
reduces weld current delivered to the
stud. The coiled cables act like a large
inductor and inhibit the flow of
energy.
Ensure weld and ground cables are not coiled during the stud welding
process.
Improperly set power supply controls. Refer to the
Section 3 Normal Operation
within the Operating the
Capacitor Discharge NCD+ Stud Welding Unit manual.
Improperly formed tip on stud due to
manufacturing process.
Replace stud with one that is correctly formed.
Changes in alloys being welded.
Changes in alloys can usually be compensated for by changing the
settings on the power supply.
Equipment failure.
Refer to the
Section 3 Normal Operation
within the Operating the
Capacitor Discharge NCD+ Stud Welding Unit manual.
Varying gauges of sheet metal.
Changes in sheet metal can usually be compensated for by changing
the settings on the power supply.
Springs inside weld tool have fatigued
and don’t apply the same pressure.
Return weld tool to Nelson for service.
