Additive manufacturing, sometimes known as 3D printing, is exactly what it sounds like. Working from a computer-generated model, a "printer" puts down layer after layer of material, adding layers until the design is realized in a finished part.
Admittedly, there's a lot of hype attached to this new technology. But there's plenty of real-world promise, too. Penn State's Center for Innovative Materials Processing through Direct Digital Deposition, known as CIMP-3D, aims to be a world-class resource for that resurgence.