The idea behind 3D printing is simple: A machine that is able to move in 3 directions, deposits a certain material on a platform according to a model generated with a computer, so that in the end, from raw materials, one gets a fully formed object, that previously only existed on the computer screen.
On the open source community these machines have been thriving and there are several models out there, with differences on the material they use to create the objects (plastic, metal, live tissue, edibles, resins), the way materials are deposited, and build complexity. The plans for building one can be downloaded for free, or kits can be bought (as in 19/02/14) for as little as 400€.
On the research framework, these machines can be used to print customizable lab equipment, such as a lab jack, lens holder, motorized micropositioners, and micropippetes. A good source of freely available models can be found at thingiverse.
Some examples of available printers are (the list is definitely, much bigger and not all printers listed here are open source):
Plastic deposition printers:
RepRap: The reprap is an open source project that hosts a family of printers, varying in build complexity and print volume. «The RepRap is humanity’s first general-purpose self-replicating manufacturing machine«, since a lot of the parts that compose the printers are 3D printed.
k8200: Sold as a kit by the Velleman company, the k8200 has a print volume of 20X20X20 cm.
Makerbot: Has a family of already assembled 3D printers and 3D Scanners.
Deezmaker: This company offers more than one printer and they also run classes on arduino, 3d printing software and others.
Terawatt industries: They offer a range of printers, some original designs and some terawatt flavour of already established printers
3D stereolithography printers:
Peachyprinter: Although not in the market yet (19/02/14, they are still managing products for their crowdfunding campaigns), the project aims, via a very clever design, to bring down the costs of a 3D printer to the U$100.00 line.
Form 1: On the high price spectrum.
B9creator: Open source printer, their website host a store and also the blueprinters, so you can build one of these yourself.
3D print on demand
If you don’t want to buy a 3D printer you can also get 3D prints on demand. Below are links for companies that will print a 3D model for you:
https://www.3dhubs.com/ – Not exactly a company, but a hub that logs printers of random people willing to print pieces for a fee
3D model repositories: