3-D printing is an additive layer manufacturing technique used to create three-dimensional objects out of many different materials. Materials capable of being 3-D printed include thermoplastic polymers, ceramics, and even conductive materials like metals. The most common materials being printed are plastics such as poly(lactic acid) (PLA) and Acrylonitrile butadiene styrene (ABS). The 3-D models are generated on computer automated design software such as AutoCAD and then sent to a three-dimensional printer to fabricate the required structure. This makes the technique advantageous to manufacturers of customized materials and designers who would benefit from rapid prototyping.
The 3-D printer works very similar to how a glue gun works except on three movable axes. A long polymer filament is passed through a heated die and the molten plastic is added layer by layer to form the object. With the open source RepRap movement, a 3-D printer can be sourced for approximately $500 making it available to virtually anyone with enough tabletop space. At the moment it is mostly a hobbyist area but large companies are beginning to get in on the action.
I am currently building (constantly modifying) a RepRap Prusa Mendel, named FinkrBot. You can follow my build along with other interesting 3D printing news and tutorials here or by following my 3D-printing-dedicated twitter @HephaCA. The picture above shows the build in an early stage before the electronics and extruder were added.