Long lead times for forged or cast metal components pose challenges for many industries, especially when parts have to be sourced from abroad. According to Bill Peter of the Oak Ridge National Laboratory, lead times of months or even years slow innovation and are particularly critical in energy- and security-relevant applications. Against this backdrop, large-format metal 3D printing is coming into focus as an alternative manufacturing method.
At ORNL’s Manufacturing Demonstration Facility, a research team is working together with Lincoln Electric on further developing Wire Arc Additive Manufacturing, or WAAM for short.
“WAAM enables complex shapes and multi-material deposition,” Peter said. “With such freedom of design, however, how do I know I’m depositing the right geometry, achieving the right material properties and performance? How can I improve fabrication rates and cost-effectiveness?” he added. “These questions shaped our collaboration.”
“We worked as true partners. Both teams’ contributions were vital for proving out the new technology,” said Jason Flamm, Lincoln Electric Additive Solutions general manager.
The process is based on automated arc welding technology, in which an industrial robot melts metal wire and deposits it layer by layer. This makes it possible to produce large-volume components with comparatively high build rates, which is particularly relevant for tools, molds, and structural components.
A central focus of the collaboration was process control. Parameters such as welding speed, current, and heat input have a significant influence on the geometry and material properties of the printed parts. To better understand these relationships, ORNL used neutron scattering at the Spallation Neutron Source, among other techniques, for material analysis. The results fed directly into the optimization of the printing systems. As early as 2017, the partners publicly demonstrated the technology with an additively manufactured excavator arm.
“ORNL helped us envision this technology’s future,” said Mark Douglass, business development manager for Lincoln Electric Additive Solutions. “The MDF provided exposure to industries and customers we normally didn’t interact with. They helped us identify new applications, like aerospace tooling.”
“We’d demonstrated WAAM’s effectiveness for producing large parts in low volumes,” said Joshua Vaughan, group leader for Manufacturing Robotics and Controls at ORNL. “But key parts for energy and defense can be so huge, a single robotic arm would still take too much time.”
Another development step is the multi-robot system MedUSA, in which several welding robots work in a coordinated manner on a single component.
“We’ll keep going bigger and faster,” Vaughan said. “We’ll continue adding intelligence into the system to increase user-friendliness and drive broader adoption. We also want to leverage machine learning and data analytics to cost-effectively evaluate part quality.”
“Lincoln Electric is ready to push this technology to commercialization, as we did our current system,” Flamm said.
“We’ve had a lot of success,” Douglass said. “But there’s so much more to explore, like digital parts qualification, to keep expanding the market.”
“The MDF is uniquely qualified to support industry in this ongoing journey,” Flamm said.
For industry, the project shows that large-format additive manufacturing can cover not only prototypes but also function-critical components. With shorter lead times and digital process chains, metal 3D printing is thus gaining importance as a complement to conventional manufacturing methods.
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