On Fri, 07 Apr 2006 14:48:25 GMT, RoyJ wrote:
I always thought the 'arc force' control squared off the edges of the
sine wave to give a better 'punch through' voltage. Suppose I'll have to
put a 'scope on the output of the stick welder and have a look!

As for what it does for you, increasing the 'arc force' sure helps on
rusty or dirty material. Increases the spatter tho.

Roy, I received some helpful answers here and tried to dig some
information myself. Here's a little summary.

The story, I think, is as follows: (as Don said) on CC welders, when
the electrode is very close to or shorts to work piece, the voltage in
the arc drops dramatically and the current at that voltage does not
produce much power (power = voltage * current).

Because of low power, there is not enough heat and electrodes stick to
workpieces. Very annoying, as it messes with fitup, finish and is
generally unpleasant.

To correct it, good welding machines have a "DIG" or "ARC FORCE"
adjustment, that increases current when the welder detects a short arc
or short circuit condition by seeing low circuit voltage. That instant
current increase increases power in the arc, and that instantly "digs"
a little hole in work by melting it (and melts more electrode) so that
a longer arc is maintained.

That prevents electrode sticking and can help increase penetration.

i