Did you ever see something on your computer or television that you wish you could push a button and have it appear before you? Well it is more of a reality than most people might think. 3D printers can use a verity of different plastics to create solid models, and these models can have moving parts right out of the printer. The printer uses a 3D CAD file to build the model, and can print anything you can think. The printer has a print head that melts plastic rods—that come on spools, and come in a variety of different colors—and is then extruded through a hollow nozzle. The print head then moves on an X and Y axis, laying down the material layer upon layer until it has finished. These models are good for: prototyping, checking your designs before they go to production; mass production, using the printed product to use in a final product or as a final product itself; and in personal use, to use in hobbies like train models or for any model enthusiasts. There are many applications for 3D printing and they come in a variety of sizes.
Here is an example of how they work: http://www.youtube.com/watch?v=Ak03wmi-3FE
threeDworks 