Toward the end of July a couple friends and I had the chance to drop in to the first New England RepRap usergroup meeting. RepRap is short for Replicating Rapid Prototyper (a.k.a. 3D printer), the goal being an open-source machine design capable of making most of its own parts. The machine itself consists of a lightweight metal scaffold (made from inexpensive standard aluminum tubing and/or Home-Despot-grade threaded rod), a flat (wood/plastic) table, a printhead, and some stepper motors to move the table up and down (Z) and the printhead in the X and Y directions. The “printhead” (rather, extrusion head) pulls a thin strand of thermoplastic from a reel (kind of like extremely thick fishing line) into the moving head, where it is heated to its melting point and, on command, pooped (extruded) out of a nozzle onto the table starting at surface level. Successive layers of molten plastic are laid down, one on top of the next, to create a finished 3D plastic part.
Here are some photos and a video of a machine in action. This particular machine is an older design, and didn’t seem to have survived the transport to the meeting very well (and based on the printed parts shown at the meeting, might have still been a work in progress – the RepRap blog shows the machine is capable of some much nicer parts). Still, it was cool to see an emerging disruptive technology such as this one in a state that proves its feasibility.