Regulation of drop-on-demand e-jet printing based on minimum pulse width and critical frequency

Abstract

Drop-on-demand E-Jet printing enables the precision preparation of micro- and nanodots, which has great applications in micro/nanostructure fabrications. However, to accurately regulate the size of the printed dots is still a challenge. In this paper, we propose a method to control the diameter of the E-Jet printed dots by predicted pulse width and jetting number based on the minimum pulse width and critical frequency, achieving precise dot size regulation within one single pulse width. Firstly, relationship between process parameters and Taylor cone formation time T_f, liquid jetting time T_j, meniscus retraction time T_r, minimum pulse width T_pwm, as well as critical frequency f_c are systematically studied. Then the relationship between pulse width and jetting number within on pulse cycle is established. Subsequently, the random forest regression (RFR) model is applied to predict the minimum pulse width and critical frequency. The predicted pulse widths for desired numbers of jets are applied to print microdot arrays of different sizes. This proposed real drop-on-demand E-Jet printing method could be applied to micro- and nanostructure fabrications for flexible electronics and printed electronics.