Their new technique can produce furniture-sized aluminium parts in only minutes.
MIT researchers have developed an additive manufacturing technique that can print rapidly with liquid metal, producing large-scale parts like table legs and chair frames in a matter of minutes. Their technique, called liquid metal printing (LMP), involves depositing molten aluminium along a predefined path into a bed of tiny glass beads. The aluminium quickly hardens into a 3D structure.
The researchers say LMP is at least 10 times faster than a comparable metal additive manufacturing process, and the procedure to heat and melt the metal is more efficient than some other methods. The technique does sacrifice resolution for speed and scale. While it can print components that are larger than those typically made with slower additive techniques, and at a lower cost, it cannot achieve high resolutions.
For instance, parts produced with LMP would be suitable for some applications in architecture, construction, and industrial design, where components of larger structures often don’t require extremely fine details. It could also be utilised effectively for rapid prototyping with recycled or scrap metal.
In a recent study, the researchers demonstrated the procedure by printing aluminium frames and parts for tables and chairs which were strong enough to withstand post print machining. They showed how components made with LMP could be combined with high-resolution processes and additional materials to create functional furniture.
“This is a completely different direction in how we think about metal manufacturing that has some huge advantages. It has downsides, too. But most of our built world the things around us like tables, chairs, and buildings doesn’t need extremely high resolution. Speed and scale, and also repeatability and energy consumption, are all important metrics,” says Skylar Tibbits, associate professor in the Department of Architecture and co-director of the Self-Assembly Lab, who is senior author of a paper introducing LMP.
They used LMP to rapidly produce aluminium frames with variable thicknesses, which were durable enough to withstand machining processes like milling and boring. They demonstrated a combination of LMP and these post-processing techniques to make chairs and a table composed of lower-resolution, rapidly printed aluminium parts and other components, like wood pieces.
Moving forward, the researchers want to keep iterating on the machine so they can enable consistent heating in the nozzle to prevent material from sticking, and also achieve better control over the flow of molten material. But larger nozzle diameters can lead to irregular prints, so there are still technical challenges to overcome.
“If we could make this machine something that people could actually use to melt down recycled aluminium and print parts, that would be a game-changer in metal manufacturing. Right now, it is not reliable enough to do that, but that’s the goal,” Tibbits says.
“At Emeco, we come from the world of very analogy manufacturing, so seeing the liquid metal printing creating nuanced geometries with the potential for fully structural parts was really compelling,” says Jaye Buchbinder, who leads business development for the furniture company Emeco and was not involved with this work.
“The liquid metal printing really walks the line in terms of ability to produce metal parts in custom geometries while maintaining quick turnaround that you don’t normally get in other printing or forming technologies. There is definitely potential for the technology to revolutionize the way metal printing and metal forming are currently handled.”
