Scientists from the Massachusetts Institute of Technology (MIT) have unveiled a new study which portrays the efficiencies of Liquid Metal Printing (LMP) for large-scale building and architectural applications.
In their LMP 3D printing method, a stream of molten aluminum is discharged onto a surface of tiny glass beads, where it promptly solidifies into a three-dimensional structure. Despite loss in surface resolution and precision, this approach greatly enhances speed. Evidently, LMP constructs 3D printed metal frameworks 10 times quicker and more cost-effectively than other metal additive manufacturing procedures.
Even though LMP isn’t a novel technology, the scientists proclaim that this is the inaugural study that exhibits its effectiveness in swiftly manufacturing large-scale components for architecture and construction purposes.
The study, published by the Association for Computer Aided Design in Architecture (ACADIA), additionally contends that LMP presents environmental benefits in large-format metal 3D printing. The MIT group promotes the use of LMP for quick prototyping and production employing recycled or waste metal.
The scientists utilized 3D printing to create several aluminum structures such as table and chair frames to support their theory. They observed that elements created with LMP could be merged with other materials and further processed to produce operational furniture.
“The method we’re considering for metal manufacturing is significantly different and has multiple benefits, though it certainly has its drawbacks as well,” said Skylar Tibbits, a senior study author and associate professor in MIT’s Department of Architecture. “However, most of our constructed world, including things like tables, chairs, and buildings don’t require excessively high resolution. Speed, scale, repeatability, and energy consumption are all crucial factors.”
Accelerating large-scale metal AM using LMP
An already established 3D printing technology for metals, Wire Arc Additive Manufacturing (WAAM), is especially well-regarded in the construction and architecture industries. Similar to LMP, WAAM is capable of quickly fabricating large, low-resolution structures. However, there is a drawback: parts produced via WAAM can be prone to warping and cracking since the 3D printing process often demands remelting.
LMP reportedly overcomes these challenges, as the metal remains molten throughout the 3D printing process. The MIT team’s LMP is optimized for use with aluminum. The 3D printer extrudes molten aluminum through a ceramic nozzle at high speeds into a bed of glass beds. This process can reportedly 3D print large-scale metal parts in seconds, with the molten aluminum cooling and hardening in several minutes.
Chair frame 3D printed using MIT’s LMP process. Photo via Self Assembly Lab.
During this process aluminum, chosen for its popularity in construction and the ease at which it can be recycled, is heated to 700℃ in an electric furnace. After being held at high temperature in a graphite crucible the metal, now molten, is gravity-fed through the nozzle.
As the molten material is injected directly into a granular substance, no supports are required during LMP 3D printing, allowing large-scale structures to be quickly and easily fabricated.
During the process of 3D printing, the LMP nozzle is pushed into the glass bead powder, making it impossible for users to observe the deposition of molten aluminum. In response to this, the team developed a numerical model to simulate the extrusion process, which provides an estimation of the deposited material amount at any given moment.
The LMP 3D printer’s nozzle heating assembly. Photo by Self Assembly Lab
In their study, the researchers utilized their LMP to swiftly fabricate metal furniture frames of variable thicknesses. The resulting frames were sturdy enough to endure machining procedures such as milling and boring. By integrating LMP with these post-processing methods, the MIT team was able to produce full-scale 3D printed tables and chairs.
Through this exploration, the team concluded that the LMP method offers significant potential for the construction and architectural sectors, serving both as a prototyping tool and a method for high-speed, inexpensive, large-scale production.
Looking to the future, the team will continue to iterate its LMP technology to enable nozzle heating, which would help to prevent clogging. The researchers also hope to achieve better control over the flow of molten material.
Ultimately, it is hoped that MIT’s LMP 3D printer can be made more accessible to allow users to easily 3D print large-scale parts from recycled metal.
“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,” explained Tibbits. “Right now, it is not reliable enough to do that, but that’s the goal.”
Liquid Metal Printing into a bed a glass beads. Photo via Self Assembly Lab.
Developments in Liquid Metal Printing
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