Eiffel Tower Printed In Less Than Seven Minutes

"A team led by Joseph DeSimone, a chemist at the University of North Carolina at Chapel Hill, has now refined the liquid-resin process to make it go continuously rather than in fits and starts. They made the bottom of the container that holds the resin bath from a material that is permeable to oxygen. Because oxygen inhibits the solidification of resin, it creates a ‘dead zone’ — a layer just tens of microns thick at the bottom of the container — where the resin stays liquid even when ultraviolet rays are shining on it. The solidification reaction happens instead just above the dead zone. Because liquid is always present below the slowly forming object, the researchers can pull it up in a continuous manner, rather than waiting for new liquid resin to flow in." (http://www.nature.com/news/chemical-trick-speeds-up-3d-printing-1.17122)