Researchers at the Vienna University of Technology have developed a really small 3D printer. From PhysOrg:
The basic principle of the 3D-printer is quite simple: The desired object is printed in a small tub filled with synthetic resin. The resin has a very special property: It hardens precisely where it is illuminated with intense beams of light. Layer for layer, the synthetic resin is irradiated at exactly the right spots. When one layer hardens, the next layer can be attached to it, until the object is completed. This method is called “additive manufacturing technology”. “This way, we can even produce complicated geometrical objects with an intricate inner structure, which could never be made using casting techniques”, Klaus Stadlmann explains. He developed the prototype together with Markus Hatzenbichler.
This method is not designed for large-scale production of bulk articles – for that, there are cheaper alternatives. The great advantage of additive manufacturing is the fact that is offers the possibility to produce taylor-made, individually adjusted items. The prototype of the printer is no bigger than a carton of milk, it weighs 1.5 kilograms, and at just 1200 Euros, it was remarkably cheap. “We will continue to reduce the size of the printer, and the price will definitely decrease too, if it is produced in large quantities”, Klaus Stadlmann believes.