By Paul Reider, P. Eng.
Welding is a complex process with many variables. A good manual welder often
has years, if not decades, of experience behind
a welding mask holding a torch. As the trend
toward mechanized and automated welding continues, the skills that are commonplace to most
experienced manual welders are becoming a
mystery to the average operator of a mechanized
subarc process. In addition to this, mechanized
welding can introduce new challenges that come
with welding faster and with more current.
When troubleshooting a mechanized or automated welding system, you need to identify and
resolve a few primary culprits if you are experiencing problems: overheating, lack of electrical
current isolation, and a magnetic field.
A typical human welder usually has an arc-on
time of only a few minutes at a time; this means
that the power source being used has time to
cool, as do the cables, torch, etc., as the welder
moves from weld to weld. A mechanized or
automated process usually is designed to have
as much arc-on time as possible. Equipment that
previously may have been sufficiently sized for
a human welder is now undersized for a mechanized application. Where a human welder may
have been welding for 6 minutes out of every 10
minutes, a mechanized system may be welding
for more than an hour continuously.
Usual Suspect No. 1: Heat
If heat is a culprit in your system, you will
likely see some or many of the following symptoms: the mechanized welder stops during long
welds without explanation and restarts after a
few minutes like nothing happened; connection
points of welding cables are very hot and may
show signs of melting, or lugs are discoloured; or
welding cables are hot to the touch.
Improperly sized cables in your welding circuit
can be a major cause of damage. Insufficient or
improper connection of the work lead (or welding
ground) to the workpiece is a very common problem. Sometimes cables wear out after a while
and they need to be replaced. A properly sized
welding cable does not need replacing unless it
While a mechanized welder may work for a limited period of time with an undersized cable, it
will constantly require replacing. As the price of
copper continues to rise, this replacement cost—
An operator works on a beam welding gantry system.
32 | AUGUST 2017 www.canadianfabweld.com
Troubleshoot your mechanized
submerged arc welding process