High frequency pulsed electrohydrodynamic printing with controllable fine droplets

Most electrohydrodynamic printing technologies make it difficult to achieve controllable small droplets and high printing frequency simultaneously. In this paper, we investigate the influence of voltage, nozzle diameter and conductivity on printing frequency and droplet size, and introduce a parameter control method for achieving controllable fine droplets with high efficiency. The maximal printing frequency f _pmax of about 3.5 kHz with the smallest printed droplets diameter of about 16 μm can be achieved simultaneously via a normal size nozzle (ID 160 μm). Results show that the maximal printing frequency f _pmax can be enhanced by choosing large flow rate with medium duty cycle, such as 180 nl min⁻¹–50%, and can be increased with a larger voltage value and smaller nozzle. The study also reveals that droplet size steadily decreases with increased and decreased nozzle diameter for large flow rate—duty cycle parameter group (180 nl min⁻¹–50%). Furthermore, under high frequency voltage, a lower voltage (1.8 kV) helps large-sized nozzles (30 G) generate smaller droplets. Droplet diameter control equations based on parameter adjustment are proposed. Droplet size accuracy and the effectiveness of parameter control are verified by analyzing actual dot matrix printing. (paper)