Scanning electron microscopy images of copper droplets assembled on a silicon substrate
Laser-induced forward transfer (LIFT) is an additive manufacturing technique that uses pulsed lasers for printing 2D and 3D microscale objects by locally melting a sacrificial donor film and assembling of molten droplets ejected from the donor layer on a target substrate. The technique has been applied for printing materials with a wide range of viscosities including, biomaterials, metals, semiconductors, polymers, etc. Our interest in LIFT is to explore experiments guided by numerical calculations of the heating dynamics of the donor film, transient deformation of the un-melted film, and the droplet hydrodynamics to control the feature size of printed objects based on the size of the ejected droplets and their landing accuracy on the target substrate. Ultimately, these studies will facilitate on-demand printing of microscale 3D objects with high reliability and repeatability through the LIFT technique.