Considerations of aerosol-jet printing for the fabrication of printed hybrid electronic circuits

Additive manufacturing (AM) methods are coming of age and are being used to not only fabricate non-functional prototype parts but also to fabricate high-quality functional parts such as electronic circuits. Direct-write (DW) printing is emerging as one of the more promising AM methods for the fabrication of electronic circuits. Of the various DW methods, aerosol-jet (AJ) printing offers several advantages such as providing ink stream widths as small as 10–20 μm and nozzle-to-build plate stand-off heights of 2–5 mm. These capabilities have enabled AJ printing to be used for fabricating high-quality RF components, transmission lines, and antennas, along with fully additively fabricated passive components such as resistors, capacitors, and inductors. However, in order to fabricate such components, structures with precise geometries need to be printed. Therefore, AJ printing needs to be elevated to a technique that is beyond a simple fabrication method capable of printing individual traces with low enough resistance values to be used as circuit traces. With this in mind, the steps that will enable a more mature AJ printing methodology, namely a careful control of the printed trace width, ink steam deposition rate, ink scale factor, and print speed, are presented and described in detail.