3D printers assigned to the 18th Dental Squadron create orthodontic models at Kadena Air Base, Japan, Dec. 9, 2021. A resin 3D printer is a machine that holds a vat of photosensitive liquid resin and exposes it to UV LED light beams layer-by-layer to harden the resin into a plastic 3D model. (U.S. Air Force photo illustration by Airman 1st Class Yosselin Perla)