MIT has been a hotbed for 3D-printing innovation since professors Emanuel Sachs and Michael Cima began developing one of the first practical 3D printers in the late 1980s. Chuck Hull had pioneered stereo-lithography in the mid-’80s, and others had invented processes to 3D-print plastics using lasers; the MIT technique was based on ink-jet printing technology and has been adapted to a wide variety of materials, including metals and ceramics. 3D printing is now a $7 billion industry—and it’s expected to grow by 27% annually through 2023.