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Author: Bob Page

The Many Advantages of Pulsed MIG

In the coming years, the strongest companies will prevail and those companies will likely have a strong history of cost reduction by way of improved efficiencies and output. Manufacturers and fabricators that rely on labor-intensive arcs and sparks, but continue to utilize the wrong welding processes or ignore the latest technology, may struggle to compete.

Pulsed MIG (solid or metalcore) welding is by no means a panacea for all joining operations. However, depending on your welding application, it may represent a substantial cost reduction opportunity.

What is Pulsed MIG?

Pulsed MIG is a modified spray transfer process that utilizes preprogrammed, high output frequency “waveforms” that are designed around the specific electrical requirements of a wire’s alloy content, diameter and shielding gas. Unlike traditional CV axial spray transfer that produces a generic arc and constant amperage output (dependent on wire feed speed), a pulsed spray provides the right amount of current at the right time. For example, one “peak” current detaches one molten droplet.

Translation

The tailor-made pulsed MIG arc is exceptionally stable (in part) because it adapts to changes in variables such as electrical stick out (distance between the contact tip and workpiece), travel speed and plate condition. The finished weld, therefore, is less burdened by costly spatter and clean up.

Because output current fluctuates, overall heat input is reduced which results in out of position weld capability (as puddle solidifies faster), decreased distortion, less susceptibility to undercut, and less smoke.

This all sounds very complicated but, in fact, pulse technology is easy to use. The correct waveform (for example .035”/4043 aluminum/100% argon) is simply chosen from a menu and a wire feed speed and arc length, suitable to the plate thickness being welded, is tuned in to get the arc, penetration and bead profile characteristics desired. Most pulse systems are “synergic” which means that after the arc length is set, only wire feed speed needs to be changed to weld thinner or thicker plate. With traditional CV systems, wire feed speed and voltage have to continually be re-balanced whenever plate thickness changes. Re-balancing requires skill and time.

The advantages discussed to add to weld quality, reduce weld defects and, in the end, reduce time (labor cost) required to get a finished product out the door. What’s more, today’s pulsed MIG power sources are highly reliable, energy efficient, and affordable (starting at $4,500).

Application

Pulse technology can be used in conjunction with solid or metalcore MIG wires of almost any alloy (including carbon, nickel, stainless, aluminum, chrome moly, and silicon bronze). Applications include a high-speed thin gauge to pipe to heavy structural fabrication.