I.H. Karampelas, S. Vader, Z. Vader, V. Sukhotskiy, A. Verma, G. Garg, M. Tong, E.P. Furlani
University at Buffalo,
Keywords: magnetohydrodynamics, drop-on-demand printing, printing molten metal droplets, 3D liquid metal printing, additive manufacturing, induction heating
Summary:At present, most 3D metal printing applications involve metal powder sintering or melting under the influence of an external energy source such as a laser (e.g. Selective Laser Sintering (SLS) and Direct Metal Sintering (DMLS) or an electron beam (e.g. Electron Beam Melting (EBM)) to form solid objects. One potential disadvantage of such methods is the increased energy cost of powderizing the metal in advance of the 3D printing process. We demonstrate a novel magnetohydrodynamic (MHD)-based method for drop-on-demand (DOD) printing of molten metal droplets into 3D objects. In this approach, a solid metal wire is fed into a DOD printhead and liquefied to create a reservoir that fills an ejection chamber that has a nozzle. Once the chamber is filled, a pulsed magnetic field is applied that permeates the chamber and induces a MHD-based pressure pulse within the liquid metal that causes it to be ejected out the nozzle in the form of a droplet. The velocity of the ejected droplet is typically in the range of several meters per second, the magnitude of which depends on the applied pressure. The droplet is projected onto a substrate where it cools to form a solid mass. 3D solid structures are formed by dropwise coalescence and solidification of neighboring. In this talk we present advances in the development of a prototype MHD-based 3D metal printing system along with sample printed structures. We discuss the underlying physics governing the drop generation process and present computational models for predicting device performance.