Wire-feed 3D printing grows in popularity

Arc welding has been a manufacturing workhorse since the early 20th century. And there’s still plenty of pep in its step as manufacturers find new ways to apply the 120-year-old technology.

A good example is wire-feed 3D printing. This additive manufacturing (AM) technique is finding favor in industries like aerospace and heavy equipment, where oversized, monolithic structures are desirable.

-- A 14- by 11- by 5-m hybrid machine is being built in Europe that’s capable of 3D-printing structures 6 by 2 m and that weigh 2,000 kg. Called the Large Additive Subtractive Integrated Modular Machine, it features a wire and arc AM system and two robotic arms, one for milling and the other for 3D-printing steel or aluminum structures.

-- Relativity Space is using its custom-designed 3D printer to build rockets. Called Stargate and dubbed the “world’s largest 3D printer,” it relies on a high-powered laser and plasma arc technology to melt and fuse wire during the printing process.

-- Oak Ridge National Laboratory (ORNL) is working on a system with Wolf Robotics that features a GMAW (gas metal arc welding) system for welding wire.

Major appeals of wire-feed 3D printing are that the underlying technology—welding wire—is well-understood and broadly accepted. Moreover, arc welding is a high-throughput, near-net-shape process and robotic welding arms and other components that comprise a wire-feed AM system are readily available off the shelf. So is wire feedstock, which, in most cases, costs considerably less than the powders other metal printers use.

There are downsides to wire-feed 3D printing, though, with the most prominent being the stair-stepping visible on a printed part’s edges and the need to surface-finish parts on a CNC machine.

But as industry increasingly looks to 3D printing to provide mass-production solutions, it’s certain that more research will focus on improving the technology.

Two research papers on the subject were recently published by ORNL and Voestalpine Böhler Welding. They each provide a good overview of wire-feed AM.