I must say, I’m very impressed by the ingenuity and continued progress that can result from open source projects. There are a few well documented online community projects in the world of rapid prototyping. Of those, the most notable are fab@home and RepRap.
Each of these websites offers an online community, a detailed set of plans and instructions, CAD files, and a bill of materials to get started. Another similarity is that each process uses an automated extrusion nozzle to deposit layers of material. While the technology has yet to catch up with the build quality of systems such as those offered by Stratasys or Dimension, development is ongoing though forum participation and blogs. Someday these systems may even rival commercial technologies.
The RepRap community has set for iteslf the lofty goal of producing a rapid prototyping machine that can actually replicate itself.
Not counting nuts and bolts RepRap can make 60% of its parts; the other parts are designed to be cheaply available everywhere. This is an interesting coincidence: we can make 60% of our proteins; the other parts are evolved to be cheaply available everywhere…
The primary goal of the RepRap project is to create and to give away a makes-useful-stuff machine that, among other things, allows its owner cheaply and easily to make another such machine for someone else.