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Nesma Aboulkhair

University of Nottingham

Jetting of high temperature metals using the droplet-on-demand technology “MetalJet”

The pace of development in metal Additive Manufacturing (AM) is ever-growing. This is stimulated by their extended capabilities in fabricating exceptionally complex structures with high degrees of intricacy that cannot be otherwise realised, i.e. using the conventional subtractive techniques. Powder-bed Fusion (PBF), Directed Energy Deposition (DED), and Laminated Object Manufacturing (LOM) are among the technologies receiving significant attention both on the research and industrial levels.

Despite the many advantages of these processes, they have some limitations on the smallest feature size attainable, the quality of the surfaces produced, and the repeatability in terms of quality and properties. In addition, there are the health and safety risks associated with handling metal powders in the respective technologies. In order to fully exploit the capabilities of additive manufacturing, research efforts need to be extended to explore the multi-material printing for multi-functionality field. The current state of metal AM technologies does not allow intra-layer multi-material printing due to the processes’ operational constraints.

In this talk, we introduce the Metaljet system, which is a novel droplet-on-demand (DOD) technology capable of ejecting and depositing tens-of-microns-sized droplets from high temperature conductive metals to fabricate three-dimensional structures with unprecedented precision. Additive manufacturing techniques adopting the droplet-on-demand approach are gaining wide popularity for their promises of saving precious resources through dispensing minute amounts of materials. Furthermore, the technology used in this study is equipped with 4 printheads allowing multi-material printing, both inter- and intra-layer. This is a real step towards digital metal printing.

Metallic specimens were fabricated using MetalJet; these were made from Sn, as a low temperature metal example, and Ag and Cu demonstrating the capability to print high temperature pure metals. Drop-on-drop interaction and bonding were analysed for the range of metals used in this study. The influence of changing the substrate material, metallic and dielectric materials, has also been investigated using state-of-the-art characterisation techniques, showing how the choice of substrate material is governed by the jetted material to fulfil the material compatibility criteria. Three dimensional complex and self-supporting structures were fabricated to showcase the range of capabilities of the system.

Biography

Nesma is an Anne McLaren Fellow in the Centre for Additive Manufacturing at the University of Nottingham. She has been working in the field of Additive Manufacturing since 2013, when she started her PhD in Materials Engineering and Materials Design at Nottingham. She has a good track record of scientific publications and funding. Her active research projects span across several metal additive manufacturing processes, including powder-based and droplet-on-demand. Coming from a mechanical engineering background, her research interests are mainly experimental with focus on materials processing, manufacturing, and characterisation for metallurgy and mechanical properties. In addition, she has growing interest in new materials for metal additive manufacturing.

Nesma is a member of the Early Career Researchers committee for the Association of Industrial Laser Users magazine. She is also involved in a range of outreach activities to raise the public’s awareness about Additive Manufacturing. She has been awarded numerous awards and honours.

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