Pulsed MIG enhances welding performance

Aluminium fabricators in Asia get overanxious on purchase price vs. life cycle costs of using the right welding process and system for welding aluminium. Most of the time, they weld aluminium with the same processes and systems used for steel.
The properties of aluminium differ greatly from those of steel, and those properties create welding challenges. Some of the common issues include: excess heat input leading to burn-through or warping on thin materials, poor bead appearance, wire feeding issues, including bird's nests, burnback and erratic feeding, difficulty meeting production goals/customer deadlines, difficulty training operators/finding good welders, excess spatter, grinding or post-weld rework, poor fusion or over-welding, bleed-through on the back side of the weld, and can only weld in the flat or horizontal position.
Fortunately, the newest generation of pulsed MIG welding systems addresses these issues. Even better, they generally provide a quick return on investment through increased productivity, reduced downtime and better weld quality.

Pulsed MIG

Because aluminium quickly transfers heat away from the weld area, establishing the weld puddle takes more energy than with steel. However, because aluminium has a relatively low melting point, thin sections of aluminium (which have less mass to transfer heat) are especially prone to burn-through and warping. In short, there's a fine line between providing sufficient energy to ensure good fusion, yet controlling the heat input to prevent problems.
In many aluminium applications, such as trailer, truck body and components (e.g., cargo boxes), boat and sign fabrication, material thicknesses tend to be 3/8-inch. and thinner. For thin components, the pulsed MIG welding process solves heat control issues.
For heavy sections of aluminium, pulsed MIG provides the ability to weld out-of-position. This eliminates the need to reposition the weldment, saving time (the spray transfer process is only suitable for welding in the flat and horizontal positions because the weld puddle is so fluid that it would otherwise roll out of the joint). Pulsed MIG also provides better control over the weld puddle, enabling new operators to easily learn the process and experienced operators to control bead appearance.

Pulsed MIG works well with both thin and thick sections because it is a modified spray transfer process. The welder switches between a high peak current and a low background current 120 to 200 times per second. The peak current pinches off a spray transfer droplet and propels it toward the weldment. The background current maintains the arc, but the heat input is too low for metal transfer to occur.

Pulsing technology

New pulsed MIG systems feature built-in pulsing programs for 4000 and 5000 series aluminium wires in .035- and .047-inch (3/64th) diameter (as well as mild steel, stainless steel and other wire types). Most importantly, the systems are operator-friendly. In many cases, all operators do set wire feed speed to match the application: use faster speeds for thicker material and slower speeds for thinner material. The systems adjust all other voltage and pulsing variables automatically.

“The newest generation of MIG welding generally provide a quick return on investment 

  through increased prNike Air VaporMax