Deposition behavior optimization of on-demand tin droplet with gravity based on piezoelectric micro-jet

Metal droplet ejection has a wide application prospect in the field of additive manufacturing in recent years. Dispensing the droplet along the gravitational direction has been invested by many studies and offers favorable performances in applications. However, the oblique impact and asymmetric deposition process of metal droplets caused by gravity are still unclear which might limit the applications, such as the processing of metal components in space and the irregular 3D surface repair. In this work, the deposition behaviors of molten tin droplets under different process parameters are studied, and the optimization of process parameters under the effect of gravity is proposed for the deposition of on-demand droplet based on a piezoelectric micro-jet device (PMJD). To accomplish this, the theoretical models are established to build the mapping relationships among the process parameters, impact dynamic and solidification process of the droplet. Meanwhile, the temperature effects of the droplet and substrate on the dynamic contact line and maximum diameter are simulated; the asymmetric deposition behaviors of the droplet under different impact velocities and solidification time are also analyzed. Moreover, the final solidification shapes of the droplet corresponding to the process parameters are measured. The results indicate that the effect of gravity on the deposition behavior is restrained by increasing the impact velocity and solidification time; and the reliability of the theoretical models and simulation results is also validated (c) 2022 Elsevier Ltd. All rights reserved.