3D Printing

Rapid liquid-metal 3D-printing process produces large parts in minutes

Rapid liquid-metal 3D-printing process produces large parts in minutes
Researchers have built a machine that melts aluminum, keeps the molten metal in a container and then feeds it through a nozzle for rapid 3D printing of components
Researchers have built a machine that melts aluminum, keeps the molten metal in a container and then feeds it through a nozzle for rapid 3D printing of components
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Researchers have built a machine that melts aluminum, keeps the molten metal in a container and then feeds it through a nozzle for rapid 3D printing of components
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Researchers have built a machine that melts aluminum, keeps the molten metal in a container and then feeds it through a nozzle for rapid 3D printing of components
The researchers demonstrated the LMP process by printing aluminum table legs and chair frames
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The researchers demonstrated the LMP process by printing aluminum table legs and chair frames
The LMP process can print complex objects quickly, but does so at relatively low resolution
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The LMP process can print complex objects quickly, but does so at relatively low resolution
The shape of the printed object can be varied by adjusting the feed rate of the liquid metal at the nozzle
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The shape of the printed object can be varied by adjusting the feed rate of the liquid metal at the nozzle
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Researchers have come up with a 3D printing method using liquid metal that's claimed to produce structures at least 10 times faster than existing metal additive manufacturing processes, though it does so at the expense of fine detail.

The liquid metal printing (LMP) process was developed by a team that included Skylar Tibbits (co-director of MIT's Self-Assembly Lab, and associate professor in the Department of Architecture) and Zain Karsan (a PhD student at ETH Zurich), and was part-funded by the Aisin Group, Amada Global and furniture company Emeco.

Inspired by previous work with rubber, the research group first constructed a "bread-loaf-sized" electric furnace to heat up aluminum – a commonly used material in construction – beyond its melting point. The liquid metal is then held within the machine's graphite crucible before being gravity-fed through a ceramic nozzle.

"Molten aluminum will destroy just about everything in its path," said Karsan. "We started with stainless steel nozzles and then moved to titanium before we ended up with ceramic. But even ceramic nozzles can clog because the heating is not always entirely uniform in the nozzle tip."

The molten metal is extruded onto a predetermined path formed on a print bed of 100-micron glass beads, where it hardens to form a 3D structure without needing supports.

Unfortunately, though the technique proved faster than other additive manufacturing methods using metal, and can produce larger objects, it does so at relatively low resolutions – meaning that the aluminum chair frame pictured below ain't pretty, but is functional.

The researchers demonstrated the LMP process by printing aluminum table legs and chair frames
The researchers demonstrated the LMP process by printing aluminum table legs and chair frames

However, the team says that the development could not only make use of recycled or scrap metal, but could find use in construction and industrial design where high resolution is not a vital attribute. The printed material can also withstand post-machining like milling.

"This is a completely different direction in how we think about metal manufacturing that has some huge advantages," said Tibbits. "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."

Another advantage over existing methods, such as wire arc additive manufacturing that's common in architecture projects, is that because the metal is molten throughout the printing process, it's less susceptible to cracking and warping.

The team plans to keep tweaking the process for improved flow control and more consistent nozzle temperatures to prevent clogging.

"If we could make this machine something that people could actually use to melt down recycled aluminum and print parts, that would be a game-changer in metal manufacturing," added Tibbits. "Right now, it is not reliable enough to do that, but that’s the goal."

The development is introduced in a paper that was recently presented at the Association for Computer Aided Design in Architecture Conference. The video below has more.

Printing furniture with liquid metal

Source: MIT

View gallery - 4 images
4 comments
4 comments
Ric
What’s not clear is whether this printer can print outside of a single plane or not. That said, in the hands of a gifted designer, the artifacts of this rough hewn process could be gorgeous in a variety of furniture and industrial design uses as well as some architectural detailing/ornamental structures.
dave be
Seems like it would be faster and more accurate to just do open air casting with the same metal. But thats how things start out, will be really cool if they manage to refine it more.
jimbo92107
Obviously this has just been invented. Have they tried it with magnesium alloy?
paul314
@Ric one of the bits in the video appears to show a piece that's extruded along a bowl-shaped surface.

But nothing that looks as if it had been made in multiple connected passes. My guess is that (at the current level of development) interlayer adhesion would not be good. You'd probably need the whole apparatus in an inert atmosphere for that, and maybe some way of displacing the glass beads just before deposition.

I wonder if it would ultimately be more effective to 3D print in some other material and then do the equivalent of lost wax casting.