designing an easy to build open source 3D printer

Hi, I'm trying to design an open source 3D printer that should be easy to build, doesn't require any 3D printed parts (all custom parts should be made out of plates) and the other parts should be standard parts (CNC) you can easily buy on ebay. I'm as well playing with the idea that you could make the custom parts out of cardboard (since they are so simple) and then print parts that are similar to reprap's, so one design would be made with 3D printed parts. It's supposed to be a low cost (300-500$) printer. I wanted to build a cheap open source 3D printer but didn't find anything I liked so I decided to design a simple printer I would like. If I'm already designing it I can as well make it open source for others.
I tried to put together some concepts in SketchUp, this is how it looks so far, what do you think, tips, suggestions?
the collection of the designs: [i39.servimg.com]
the gallery with bigger pictures: [imageshack.com]
or [www.servimg.com]

Other makers have built cardboard and paper printers - if you do a search you might find something.

---

_______________________________________
Waitaki 3D Printer

How about a milk crate.

[www.instructables.com]

Mike

Extremely inefficient use of design. Look up V-Slot, a super majority of your framing can be one stop shopping.

---

Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

Ord bot?

[reprap.org]

not so sure about card board, i think you may be better off with mdf
ala buildyourcnc.com