I've been working on a simple design for a RepRap Mendel inspired 3D printer, buildable from wood and metal beams (I've abandoned my previous boxed reprap design for now). The design goals are:
- Keep the design simple
- Keep construction easy
- Keep material costs low
- Keep the machine functional
I used OpenSCAD for the design. It's a CAD program that creates the model from a script. This allowed me to make the design parametrized, allowing you to specify the size of the used wooden beams, motor type, rod diameter, and target size of the machine as parameters. My script even prints out a part list with the measures of each part and the calculated print volume (unfortunately it isn't possible to calculate hole drilling positions).
Not counting fasteners, bearings, or the print head, the current design has 40 parts; 16 lengths of wooden beam, 6 threaded rods, 6 smooth rods, 5 pulleys, 3 belts, 3 motors, and the print surface. The maximum print volume for the current default configuration is 25*20*20 cm.
By tilting the side support rods inwards towards the top I hope to increase the resistance against sideways shearing forces.
I haven't designed the print head yet, I'll probably take a closer look at what nophead, wade, and the mendel and makerbot teams have achieved in that area, and maybe just go with pre-printed parts for it.
The OpenSCAD files are available on github, feel free to play around and borrow from them. Once I've built the design and verified that it works well, I'll upload it to Thingiverse.