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       Their technology, called liquid metal printing (LMP), involves depositing molten aluminum onto a layer of tiny glass beads in a pre-determined pattern.
       Imagine printing a table leg or chair frame out of liquid metal in minutes. Researchers at MIT have developed a new additive manufacturing technology that could make it possible.
       Their method, called liquid metal printing (LMP), involves depositing molten aluminum in a controlled path onto a layer of tiny glass beads. The aluminum quickly solidifies into a 3D structure, ready for use or further processing.
       The researchers claim that LMP is at least ten times faster than comparable metal additive manufacturing processes, and that the process of heating and melting the metal is more efficient than some other methods. However, LMP also has its limitations. The technology sacrifices resolution for speed and scale, and cannot achieve high resolution.
       However, LMP is not without its limitations. The technology sacrifices resolution for speed and scale. While it can print larger parts than those typically made using slower additive manufacturing technologies, and at lower cost, it cannot achieve high resolution.
       In a recent study, scientists demonstrated the process by printing aluminum frames and components for tables and chairs that were strong enough to withstand post-printing processing.
       They demonstrated how laser-printed parts (LMP) can be combined with high-resolution processes and other materials to create functional furniture. LMP is suitable for applications in architecture, construction and industrial design, where parts of large structures often require less detail. It can also be used for rapid prototyping using recycled or scrap metals.
       A common metal printing method in the construction industry, called wire-arc additive manufacturing (WAAM), can produce large, low-resolution structures. However, because some parts must be re-melted during the printing process, these structures are susceptible to cracking and warping. Laser melting manufacturing (LMP) keeps the material molten throughout the process, avoiding some of the structural problems caused by re-melting.
       “It’s a completely different way for us to think about metal fabrication, and it has some huge advantages. Of course, it has disadvantages. But most of the things we build in the world — like the tables, chairs, and buildings around us — don’t require extremely high resolution. Speed, scale, repeatability, and energy consumption are all important metrics,” said Skylar Tibbits, an associate professor of architecture, co-director of the Self-Assembly Lab, and senior author of the paper presenting the LMP.
       The researchers built a machine that melts aluminum, holds the molten metal, and shoots it out of a nozzle at high speed. Large parts can be printed in seconds, and the molten aluminum only takes a few minutes to cool. The team chose aluminum because it is common in construction and can be recycled cheaply and efficiently.
       The researchers tried a variety of materials to fill the print bed, including graphite powder and salt, before settling on 100-micrometer glass beads. These tiny beads can withstand the extremely high temperatures of molten aluminum and act as a neutral suspension, allowing the metal to cool quickly.
       The amount of molten material in the crucible, the depth of the print bed, and the size and shape of the nozzle have the greatest impact on the geometry of the final object. For example, since the amount of aluminum ejected from the nozzle gradually decreases as the crucible cavitates, the larger diameter parts of the object will print first. Changing the depth of the nozzle will change the thickness of the metal structure.
       To simplify the LMP process, the researchers developed a numerical model to estimate the amount of material deposited on the printing platform in a given time.
       Tibbits explained that because the nozzle was pressed into glass bead powder, the researchers couldn’t observe the deposition of molten aluminum, so they needed a way to simulate what should happen at certain stages of the printing process.
       They used laser printing (LMP) to rapidly produce aluminum frames of varying thicknesses that were strong enough to withstand machining processes such as milling and boring. They demonstrated how LMP could be combined with these post-processing techniques to create chairs and tables composed of low-resolution, rapidly printed aluminum parts and other components such as wood.
       LMP is a faster, greener alternative to traditional methods that could revolutionize metal production. However, the technology is still in its early stages and requires further development before it can be widely used.
       ”If we could get this machine to melt recycled aluminum and print parts, it would be a game changer in metalworking. It’s not robust enough to do that right now, but that’s our goal,” Tibbits said.