by Tim Wilson
Lightweight alloys present new welding challenges
Lightweight alloys are becoming more common, which is translating into increased demand for suitable welding applications. Examples can be found in the aerospace, marine vessel, and automotive sectors, with manufacturers developing more and more lightweight applications within specific product designs.
“The recent introduction of the Ford F-150, which is designed with all aluminum body panels, is one of the more prominent instances of using lighter weight alloys,” says Mike Vandenberg, product manager at Miller Electric Manufacturing. “That introduction brings with it the need for welding technologies that will ultimately simplify repairs for auto body shops.”
The challenge is that automotive shops typically have only been welding steel, which means operators will now have to learn to weld thin aluminum. Having a designated aluminum system can be critical to success in this area, particularly if set-up is made easy with a plug-and-play approach.
“Once running, welding systems are designed, in many cases, to offer synergetic controls, and often have other programs or preset settings designed for aluminum only,” says Vandenberg. “When the components are specifically matched to work together to weld aluminum, arc performance can also often be maximized through advanced processes or features, such as Pulsed MIG welding.”
This can also help with the challenges associated with aluminum, which has a lower relative melting point than other metals. Nonetheless, aluminum requires enough heat to ensure proper puddle formation. Without the correct welding equipment, this can potentially lead to burn-through, something that can be avoided with a push-pull system.
“With a push-pull system, a motor in the gun pulls the wire through the liner, while another motor on the feeder becomes an assist motor,” says Vandenberg. “By maintaining a constant supply of wire into the liner without buckling or bending it, the push-pull system eliminates bird-nesting.”
Vandenberg says a push-pull system can also be more ergonomic and user-friendly, since the weight of the spool is not in the welding operator’s hands, as with a spool gun. With a push-pull system, the spool of wire (typically 304.8 mm or 12 in.) also needs to be changed less often. As well, larger wire spools can be purchased at a greater discount, which helps minimize downtime during changeovers.
Shooting from the hip
Nonetheless, spool guns have their own advantages when welding light alloys. Lincoln Electric, for example, has three spool gun options, with the Magnum PRO 100SG offered at a package price of under $300.
“The product offers customers the opportunity to weld aluminum without the costs associated with push-pull welding solutions,” says Josh Zaller, product manager for commercial products at Lincoln Electric. “Those solutions can require more advanced power sources, push-pull capable wire feeders and more expensive push-pull guns.”
A cost-effective product like the Magnum PRO 100SG is best used for repair and maintenance applications. It can be set-up by a novice or a first-time user in a matter of minutes.
“By minimizing the distance between the contact tip and wire drive, feeding issues commonly associated with softer aluminum welding wire are significantly reduced,” says Zaller. “Compared to TIG welding, GMAW welding aluminum is dramatically faster and requires less skill.”
This then reduces production time and expedites welder training. Generally speaking, if a welding operator is skilled in TIG or MIG welding, it requires very little training to weld materials like aluminum, especially with the advances in welding equipment technology, which can address critical issues like wire feedability.
“Because many welding systems designed for aluminum offer Pulsed MIG welding capabilities, that simplifies the process,” says Zaller. “MIG welding with these systems also brings with it faster welding speeds, higher productivity, good weld quality and the necessary cleanliness for aluminum.” SMT
Tim Wilson is a contributing editor.