Multimaterial multinozzle 3D printheads. Credit: Nature (2019). DOI: 10.1038/s41586-019-1736-8
3-D printers are revolutionizing manufacturing by allowing users to create any physical shape they can imagine on-demand. However, most commercial printers are only able to build objects from a single material at a time and inkjet printers that are capable of multimaterial printing are constrained by the physics of droplet formation. Extrusion-based 3-D printing allows a broad palette of materials to be printed, but the process is extremely slow. For example, it would take roughly 10 days to build a 3-D object roughly one liter in volume at the resolution of a human hair and print speed of 10 cm/s using a single-nozzle, single-material printhead. To build the same object in less than 1 day, one would need to implement a printhead with 16 nozzles printing simultaneously!