High-Resolution Electrohydrodynamic (EHD) Direct Printing of Molten Metal

In this paper, we developed a high-resolution direct printing process for molten metal using Elctrohydrodynamic (EHD) printing technology. We characterized and verified the effect of the electric field on the printing process, which can continuously print fine molten metal filament from the nozzle without requiring any pneumatic pressure. By comparing direct extrusion with pneumatic pressure and EHD printing with a voltage, we found that the EHD printing can effectively reduce the printed filament dimension down to less than 50 μm and achieve better quality (uniformity and shape) of the printed features. We successfully applied EHD printing to print high-resolution 2D patterns and some high aspect-ratio 3D structures, which demonstrated the potential capabilities of EHD printing process in producing fine metal structures and microelectronic fabrication.