Dissatisfied with your plastic extrusion-based home 3D printer? Looking for a mechanical build challenge? Perhaps you'd be interested in checking out the Laser 3D Printer on Instructables.
This project describes how to build a stereolithography (SLA) machine. You should know, however, that the SLA build process is quite different from typical RepRap-style 3D printers that extrude plastic. Instead, SLA illuminates a liquid resin with UV light, creating a layer of the object when the resin solidifies when exposed to the UV light. By gradually lowering the print into the resin and fusing new layers at the surface of the liquid resin, the object is gradually built.
The advantage of this system is that the resolution can be much better than extrusion-based alternatives, since the equivalent of the "nozzle" is simply how fine you can focus the UV light.
While this looks like a great project we wonder about its legality. The SLA process has been deeply patented by commercial companies and the question must be asked whether they would permit it to proceed. Certainly if this project went into commercial business some questions would be asked. It will be interesting to see what happens.