Off the Grid: A new strategy for material-jet 3D printing with enhanced sub-droplet resolution

Drop-on-Demand additive manufacturing could offer a facile solution for scalable on-site manufacturing. With an increasing number of functional materials available for this technology, there are growing opportunities for applications, such as electronics. Here we report on a novel printing strategy, Off-the-Grid (OtG), which enables refined positioning of individual droplets and enhanced resolution compared to the traditional printing strategy. We demonstrate successful printing of structures with feature position control smaller than a single droplet size, and hence enhanced shape fidelity for intricate designs. This strategy is extended to filled patterns, enabling improved layer coverage and customisable inter-layer droplet positioning to control surface morphology. The OtG strategy is applied to produce functional designs, such as conformable circuitry and miniaturized antennae, and is transferable to different materials, from metal nanoparticle and polymeric inks on inkjet platforms, to molten metals on a MetalJet printer. These results could advance exploitation of AM in electronics, wearable electronics, medical devices, and metamaterials.