Lincoln Electric IM736-D manual Arc Control See Table B.2

B-6 OPERATION B-6

Arc Control (See Table B.2)

There are no specific unit values offered because the setting of this feature largely depends upon operator preference. Arc Control has a different effect on the character of the arc depending upon the welding process applied.

In SMAW (STICK mode), arc control adjusts the arc force. It can be set to the lower range for a soft and less penetrating arc characteristic (negative numeric values) or to the higher range (positive numeric values) for a crisp and more pene- trating arc. Normally, when welding with cellulosic types of electrodes (E6010, E7010, E6011), a higher energy arc is required to maintain arc stability. This is usually indicated when the electrode sticks to the work-piece or when the arc pops-out during manipulative technique. For low hydrogen types of electrodes (E7018, E8018, E9018, etc.) a softer arc is usually desirable and the lower end of the Arc Control suits these types of electrodes. In either case the arc con- trol is available to increase or decrease the energy level delivered to the arc.

In GMAW-S, the short-circuiting mode of metal transfer, the Arc Control features the ability to increase or decrease the energy level at the arc. Setting the arc control from 1 to 10 decreases energy, and setting the Arc Control from 0 to –10 increases the energy delivered to the arc.

Solid carbon steel electrodes in a range from .025"- .045" (.6

mm– 1.1 mm) are nominally used, and the shielding gas blend for GMAW-S is usually 100% carbon dioxide or a blend of argon and carbon dioxide. The Arc Control in this scenario is set to control the droplet size and more pinch is added (increasing pinch reduces energy to the arc) to achieve the "bacon frying" sound associated with this mode of metal transfer.

Carbon steel electrodes employed in GMAW-S usually per- form best when the droplet size is regulated by pinch to reduce the droplet size transferred with each short-circuit event.

When welding with solid stainless steel types of electrodes it is usually desirable to increase the energy delivered to the arc. High percentage argon blends with a 2 % addition of oxygen or a three part shielding gas blend comprised of 90% Helium + 7.5% Argon + 2.5 % carbon dioxide are usu- ally employed. The added energy is associated, in this sce- nario, with increasing the inductance (negative numeric val- ues). By adding to the energy level the weld bead appear- ance improves – spatter levels decrease and wetting action at the toes of a fillet weld increases. The arc is softer with the higher inductance setting and the arc lends itself to faster travel speed.

In GMAW-P, the pulsed spray mode of metal transfer, the Arc Control is, once again, used to increase and decrease the focus of the energy delivered to the arc. Increasing the setting in the range of +1 to +10 results in an increase in pulsed frequency, and the effect is to narrow the arc cone and concentrate the available energy to a smaller area. Decreasing the Arc Control setting from –1 to –10 results in a reduction of pulsed frequency – the result is a broader arc cone, which creates a wider weld bead.

Important to note here is that if a component of a pulsed waveform is increased, then another must be decreased. Adding pulsed frequency through an increase in the Arc Control setting, then also results in a proportional decrease in background current. If this were not the case, then the arc would become too long, with too much energy, and the arc would be unusable.

TABLE B.2-Arc control settings by process

PROCESS	ARC	SETTING	APPLICATION AND
	CONTROL		RESULT
	SYNONYM
SMAW (STICK)	Arc Force	Lower (-1 to -10) for	Minus settings are soft
		low hydrogen types of	and buttery for low
		electrodes. Higher (+1	hydrogen electrodes.
		to +10) for cellulosic	Plus settings are harsh
		and other types.	and digging for other
			types of electrodes.
GMAW – S (Short	Inductance or	Setting -1 to -10 for	The minus settings
circuiting metal	Pinch Control	softer higher energy	result a more fluid
transfer		arc. Setting +1 to +10	puddle and larger
		for a crisper lower	droplet size. The lower
		energy arc.	settings reduce the
			droplet size and reduce
			energy to the arc.
GMAW – P (Pulsed	Pulsed frequency	Minus settings reduces	Wider arc cone and
spray metal transfer)	control	frequency. Plus	weld bead. Narrower
		settings increase	arc cone and narrower
		frequency.	weld bead.
Pulse – on –Pulse™	Pulsed frequency	Minus settings result in	Minus settings result in
(Aluminum Only)	array control	lower array frequency	a wider bead with more
		and the plus settings	distinct ripples. Plus
		increase the array	settings narrow the
		frequency.	resultant bead and the
			ripples are less distinct.

POWER MIG 300