Avoid Producing Missing Welds!
Sometimes there are disturbances that appear
unexpectedly that will cause a missing weld. Even with
desired stable welding currents, the growth of a good
spot weld escapes. In this case shown to the left, the
current is held constant (red line) at about 10k Amps
for 250mS, however the dynamic resistance curve shows
that the weld was never completed. Something drastic
happened such as a shunting path for welding current to
avoid passing through the spot weld location.
You can continue to use constant current and have a tool
in the weld control identify that the weld is
questionable. A tool such as SoftQ will annunciate a
fault because the dynamic resistance signature is not
acceptable.