A Processing Model toward Printing High-Flatness Layers for Direct-Ink-Writing Printed Self-Leveling Inks

The direct-ink-writing (DIW) has been widely used to print various functional devices using different self-leveling inks. Due to the complicated rheological behavior and multiple processing parameters, how to rapidly determine the crucial parameter for high-precision printing is still challenging. Here we adapt a widely used commercial silver paste and identify the critical parameter for dominating the flatness through observation of the microstructure evolution for the line-to-layer forming process. An analytical model for flatness with printing parameters was established. Using the proposed model, the printing process parameters for achieving high flatness can be directly determined, avoiding the high cost of extensive experimental exploration.