On-Demand Ejection and Control of Uniform Metal Droplets

On-demand ejection of uniform metal droplets is the process of forcing tiny molten liquid metal out of a nozzle by applying a pressure pulse to form a single metal droplet. The size and initial velocity of the metal droplet depends on the shape of the pressure pulse. In this chapter, the technical features of drop-on-demand (DOD) ejection technologies utilizing Pb–Sn alloy and aluminum alloy as the ejection materials, and driven by pneumatic pulse, acoustic pulse, and stress-wave pulse are studied by combining numerical and experimental research. The influence of parameters such as the droplet size, size uniformity, and the range of controllable ejection parameters that produce uniform metal droplets are obtained for the above three ejection-driven models in order to lay the foundation for the selection of uniform metal droplet ejection technology.