Effect of Print Parameters on Print Consistency of Aerosol Jet Printed Electronics

Abstract

Recent advancements in the field of additive manufacturing have given rise to a nanomaterial ink based technology known as Aerosol-jet printing (AJP) which enables fabrication of micro scaled printed and flexible electronics. Development of test protocols, refinement of inks and print process parameters have been demonstrated within the research community largely depending on the empirical observations; however if AJP is to be utilized at a large industry scale level for fabrication and manufacturing then it is of utmost importance that the print consistency be studied as a function of not only the optimized print parameters but also as a function of the print-time over a period of 8-10 hours which is a fair representation of a standard work shift. Due to the novelty of the AJP technology no information exists which addresses the issues, if there are any, related with the print consistency of AJP. Goal of this study is to establish a basic understanding which may or may not result in process limitations and also provide guidelines for an improved process window and print parameter optimization if need be. In this research study, a 90nm particle sized silver based ink and a 70nm particle sized ink have been utilized to study the print consistency of a state-of-the-art Aerosol jet printer, Optomec 300. The print process parameters were optimized by varying the sheath rate, mass flow rate, nozzle size and chiller temperature. Using these parameters the numbers of passes were optimized as a function of least amount of line resistance. With all parameters optimized the Aerosol jet printer was allowed to print continuously for a duration of 10 hours. Printing process efficiency has been gauged a function of process capability index (C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">pk</sub> ) and process capability ratio (C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</sub> ). Later the printed samples were studied offline using optical Profilometry to analyze the consistency within the line width and line height. SEM analysis has also been conducted to verify if or if not the overall profile of the printed samples stays constant over the 10 hour period.