[NCLUG] RepRap RoadMap

[John Gilmore]

The goal is to build a McWire repstrap - something capable of printing
out the plastic parts to build a honest-to-goodness reprap. It doesn't
have to be pretty, it doesn't have to be horribly accurate, it only
has to work, and work long enough to print the parts to replace
itself. I'm going to do this. I hope to have lots of help, and to take
as many of you as I can with me.

My father is an EE working at AEI, and scrounges all sorts of useful
things. Thermistors, steppers, etc. Most of the parts that I've listed
under "We Have" are still over at his place. I figure that will
significantly reduce the cost of this project.

Per discussion at the hacking society last night, this is the status
of the local reprap project:

We Have:

3 steppers (200 step, not 400, so they won't work for darwin v1.0 but
for the McWire it won't matter.)
Power Supply - the steppers take 24 volts, but the power supply is with them.
Electronics to control the steppers
Plastic (on order, be here in a week or two)
Gearmotor for the extruder. (I'm not 100% sure the gearmotor I have
will work, but I'm confident we can mock up something functional)
Various electronic bits

We Need:

Host software updated to talk to the controller card we have.
       This is written in Java, which I've never worked with - but how hard
can it be? ;)
       I should have the specsheet on the protocol in a few days.
       I'll be working on this as time allows - which is to say, not very
much. I figure this is the place to start (for me) because I have the
steppers and board to practise with

Mcwire CNC frame
       Howto at
http://www.instructables.com/id/Easy-to-Build-Desk-Top-3-Axis-CNC-Milling-Machine/
       I would guesstimate the cost of this at around $50 (but that's
probably high)
       You'll need the steppers to mount on it to complete it.
       This is probably the next step. Takers?

Extruder controller
       We'll use the v2 arduino based controller, I think. Paul hummer said
he had them coming out of his ears.
       http://reprap.org/bin/view/Main/Generation2Electronics
       Notice that there is no "heater coil driver" to supply power to the
nichrome heater wire in response to the thermostat. I don't know
what's up with that.
       Paul hummer has volunteered to do this bit.

Extruder plastic parts kit
       $20+shipping at http://store.rrrf.org/
       This is cheap enough that I figure there's no reason not to

Extruder nozzle
       Go to http://www.reprap.org/bin/view/Main/ExtruderMechanicalParts for
a basic overview. Cheap parts mostly, but a quite a bit of filing and
shaping and whatnot. Some JB weld and some nichrome heater wire (can't
you get that from a busted toaster?) There was an interesting bit
somewhere about using a bigger drillbit, soldering the hole closed
with a bit of wire in it, the pulling out the wire to make a very
small hole of the right size. Probably a lot easier than drilling with
a wire gauge drill bit, and cheaper too. Might not do HDPE extrusion,
but we certainly don't need that on the first one.