Making a rapid prototyper

Hello all,

I've been lurking here since mid July. I apologize for not jumping in during
the self-replication thread, but I'm still catching up with my email.

I'm Sebastien Bailard, the junior-most developer for the RepRap project - a
rapid prototyper (rp) we're trying to build. It is basically a glue gun on a
three-axis CNC device. The glue gun extrudes hard plastic, polycaprolactone,
which is much like nylon but melts at 70C.

The RepRap makes plastic parts, and is made of plastic parts, so it can make
copies of itself. (At least, once you add ground drill rod, bushings,
steppers, pcbs, etc...). We're looking to put down a 0.5mm thick filament
with 0.1mm precision, a build volume about 20cm-30cm on a side, and keeping
the total (pre-fabrication) cost under about USD$500. We're _hoping_ to
achieve self-replication within 2 years.

We'll be building the RepRaps using commercial or home-built rp machines (like
a RepRap itself). Most of the developers are building what they
call "RepStraps", essentially homebuilt CNC machines, which will move an
extruder head around. I'm lazy, so I'm going to just use my Taig mill as a
RepStrap. (I suspect that's how most people on this list would go about it.)

Extruder head write-up:
http://reprapdoc.voodoo.co.nz/bin/view/Main/Version2OfThePolymorphExtrusionHead

General info:
http://reprapdoc.voodoo.co.nz/bin/view/Main/WebHome

Project Blog:
http://reprap.blogspot.com/

Print file community and database (will be at objects.reprap.org). Currently
this is just a functional, anyone-editable wiki-powered wishlist.
http://www.dubsen.org/twiki/bin/view/

We also want to design a ceramic/metal slurry depostion head to do additive
fabricating, sintering the slurry object in a furnace, along with a ECM/EDM
head.

The group is figuring out how to control it via a serial port and USB, while
writing the controller in Java, but I'm going to be building in parallel port
and emc control as well, probably.

My setup: right now, I've only got as far as milling "Hello world" in a bit of
boxwood using my taig, by flicking bits on the parallel port and having crude
stepper motor controllers (breadboarded L297 + L298 chips) move the mill
around. I'll be setting up EMC over the next couple days, and then machining
an extruder head out of plastic.

If you're interested, please take a look and tell me what you think. I would
be happy to answer any questions about the project, either on list or off.

-Sebastien Bailard