Hello everyone.
Welding newsgroup seems defunct. This may or may not be excessively abstruse .
Continuing welding, working in a FabCo. More than 4 months back at it
now.
"My" welding machine, a Miller MigMatic 320i, is a Constant Voltage
GMAW / MIG welding machine. It seems to be internally an inverter,
but is Constant Voltage output. It is an "economy" industrial machine.
Everyone else has "pulse" machines, which are minimum 5X the cost.
"My" situation is made more difficult because almost all our
thicknesses are in the 5mm to 8mm range - right where for Constant
Voltage you will be in the "globular" transition domain between
dip-transfer (lower thicknesses) to spray-transfer (higher
thicknesses) fundamental physical domains.
So I am forcing "I intend spray and finagle it to be so" or "I intend
dip and make it so".
Crazy big adjustments of both wire-feed-speed and Voltage between
different welds on the same job.
For the "pulse" machines this is a non-point - they are in pulse all
the way from low powers up to high powers, with no transition range.
Nice "just right" fluid weld pool etc. through the range.
I suspect the pulse machines with their "proprietary special
high-productivity" pulse modes sense how long the arc is and where the
weldpool surface is - that they are "fly-by-wire".
I met / found this almost 15 years ago
http://weldsmith.co.uk/tech/welding/datalog/GMAW_RapidArc_170612.html
"Waveform analysis for MIG / GMAW "Lincoln RapidArc" on steel"
As some pillock who had stumbled on this while doing a bit of
research, Lincoln told me what this does for their industrial
customers - and going back with an armful of offcuts I found that is
exactly so - it will "run" absurdly fast while keeping control of the
weld-pool and giving the sought weld bead shape.
But yes part of that pulse cycle I logged and graphed is "feeling"
where the weld pool (surface) is. "fly-by-wire" ...
Anyway - to the question...
The "pulse" machines seem to have such a broad "good zone" you simply
set the thickness, irrespective of joint geometry, etc., etc., etc -
and it welds perfectly.
With "my" CV machine, I have a great big archive of welding conditions
for each
{thickness; joint geometry; high-penetration or high-deposition; etc.,
etc.}
Then unique jobs with special conditions.
10's into maybe hundreds of them.
So the CV machine has a very very narrow "good-zone" / "sweet-spot";
while the "pulse" machine with seemingly its "fly-by-wire" has such a
wide "good-zone" that you have this "one-size-fits-all" dial-in the
thickness.
Anyone else know of this?
Rich Smith
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