Printed Hybrid Electronics for the Fabrication of High-quality Electronic Circuits

Direct-write (DW) printing is emerging as a promising additive manufacturing (AM) method for the fabrication of high-quality electronic circuits. Fully additively fabricated passive electronic assemblies such as dielectric substrates, traces, interconnects, and passive components (resistors, capacitors, and inductors) have all been demonstrated. While this is necessary, electronic circuits contain more than just passive components; therefore, hybrid fabrication methods will most likely be needed in the foreseeable future. This invokes the idea of “print what you can and place what you can’t.” what is referred to as flexible hybrid electronics (FHE) when applied to thin (flexible) substrates and as printed hybrid electronics (PHE) when applied to ‘rigid’ conformal (non-flat) surfaces. Of the various direct-write (DW) printing methods, aerosol-jet (AJ) printing offers several advantages for PHE fabrication such as providing ink stream widths as small as 10-20 um and nozzle-to-print surface, stand-off heights of 2-5 mm. These capabilities have enabled AJ printing to be used for the fabrication of PHE micro-controller circuits with functionality on par with that of a standard Arduino Mini board. Such a PHE demonstrator circuit has been designed and then fabricated using multiple form factors such as 1. a flat substrate surface, 2. the internal surface of a sounding rocket door panel (with a 16 in dia. curvature), and 3. onto the surface of a 4-inch hemisphere. The manufacturing methods used to fabricate these PHE circuits are being matured to 1. establish design rules, 2. create standard operating procedures (SOP) for both design-to-toolpath creation and parts fabrication, 3. perform full reliability testing, and 4. map out
fabrication resources (print times for given lot sizes). Progress in all these areas of effort will be presented.

D. R. Hines1, P. Li1, J. Fleischer2, B. Zhao3, A. Dasgupta3, and S. Das3
1Laboratory for Physical Sciences, 8050 Greenmead Drive, College Park, MD 20740
2Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742
3Department of Mechanical Engineering, University of Maryland, College Park, MD 20742