Characteristics of drop-on-demand droplet jetting with effect of altered geometry of printhead nozzle

Abstract

As a precision micro-electromechanical actuator, the geometry of drop-on-demand (DoD) printhead nozzle could be altered resulting from the accumulated manufacturing tolerances (AMT) and partial nozzle clogging (PNC) which largely influences the droplet jetting dynamics. To explore the effect of altered nozzle geometry on the DoD droplet formation characteristics, a three-dimensional (3D) multi-relaxation-time (MRT) lattice Boltzmann (LB) model coupled with nonideal nozzle plate wettability is presented to handle the complex droplet jetting process. For typical Z=11.57, with the hydrophobic nozzle plate, the velocities of final droplet are increased with the nozzle volume decreasing θN=49° and PNC. The non-ideal hydrophilic nozzle plate could eliminate the effect of altered nozzle geometry which exhibits the identical trajectories of droplet jetting. As Z number increasing to Z=19.8, the overall velocities of liquid filaments and resulting droplets are increased considerably. However, the effect of AMT decreases the velocity of filament tail and the recombination of satellite and main droplets could not occur for θN=49° which is undesirable for DoD inkjet printing. For case of PNC, the leftward deviation of recombined droplet is increased for the non-ideal hydrophilic nozzle plate and large Z number which greatly deteriorates the droplet jetting directionality.