ADVANCED MATERIALS & PROCESSES | APRIL 2024 68 3D PRINTSHOP COATING LETS SATELLITES TRAVEL LIGHTER Adding a coating onto 3D-printed satellite components called waveguides could allow them to retain conductivity while reducing overall payload. Researchers from Drexel University and the University of British Columbia are testing a waveguide made from 3D- printed polymers coated with a conductive nanomaterial called MXene. Waveguides function as pipelines for microwaves, directing the waves to receivers while preserving the power of the signal. “Waveguides can be as basic as a straight, rectangular channel or they can morph into shapes resembling a ‘crazy straw,’ with bends and twists,” says Mohammad Zarifi, an associate professor at the University of British Columbia. “The real game-changer, however, is the advent of additive manu- facturing methods, which allow for more complex designs that can be difficult to produce with metals.” The MXene coating emerged as a strong candidate for this application because it is highly conductive, functions as an electromagnetic shield, and can be produced simply by dipping the waveguide in MXenes dispersed in water. Other metallic paints have been tested, but due to the chemicals used to stabilize their metallic ingredients, their conductivity suffers in comparison to MXenes. In addition, the researchers reported that the MXene coating bonded exceptionally well to the 3D-printed nylon waveguides due to compatibility between their chemical structures. The team dip-coated lightweight guides of varying shapes and sizes to test MXene’s ability to thoroughly cover their interior. The MXene-coated nylon waveguides weigh about eight times less than the standard aluminum ones currently being used, and the MXene coating added just a tenth of a gram to the overall weight of the components. drexel.edu. AN EXPLANATION FOR PORE FORMATION USING DED A team from Queen Mary University, University College London, and RollsRoyce investigated the mechanisms that form pores during directed energy deposition (DED) additive manufacturing, revealing five distinct processes. DED builds intricate structures layer-by-layer, which is ideal for creating complex geometries for products. However, unpredictable formation of tiny air bubbles weakens components, jeopardizing performance and raising safety concerns. Until now, the exact mechanisms behind pore formation and evolution in DED remained a mystery. The study showed five processes that contribute to this behavior: gas bubble migration and coalescence, surface tension effects, and entrapment by solidification fronts. The researchers used advanced in situ x-ray imaging and multiphysics modeling to study the process. Their findings provide a detailed understanding of how pores form, move, and interact within the melt pool during DED, enabling the development of targeted strategies to minimize their presence. www.qmul.ac.uk. To better support and encourage growth in the Japanese ceramic 3D printing community, major manufacturers have established a technology network. The group, consisting of AS ONE, Mitsui Kinzoku, Yugyōkuen Ceramics, and Lithoz, are investing in a portfolio of 3D printing technologies for high-performance ceramics, hoping to lead the way to innovation in Japanese manufacturing. lithoz.com. BRIEF MXene-coated waveguides can direct and focus electromagnetic waves in telecommunications satellites. Courtesy of Drexel University. Pore formation dynamics during a study of directed energy deposition. Courtesy of Nature Communications. (a) (b)
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