Conceptual Design of Industrial Inkjet Head for Micro Patterning on Printed Circuit Boards

A conceptual design using computational fluid dynamics and experimental fabrication has been performed to develop an industrial inkjet head for micro-patterning on printed circuit boards. The measured displacement waveform from piezoelectric actuator by Laser Doppler Vibrometer was used as input data for the three-dimensional flow solver to simulate the droplet formation. The mechanism of droplet ejection from piezoelectric-type inkjet heads was investigated by simulating two-phase flows of the air and metal inks. As a preliminary approach, liquid metal jetting phenomena are identified by simulating droplet ejection, droplet formation, and wetting on the substrate in a consequent manner. Parametric studies are followed by the design optimization process to deduce key factors to inkjet head performance: nozzle geometry, droplet size, ejecting speed, ejecting frequency, and ink viscosity. The present design tool based on two-phase flow solver and experimental measurements has shown its promising applicability to various concept designs of industrial inkjet system for micro-patterning on electronic chips and boards.