Design Decisions

I'm trying to put all my final design decisions on this page (until I change them :-).

Layout: I am tired of having to move the solidoodle to fool around with connections on the back. Since I get to decide where to put everything on my own desing, all the stuff I'll need to play with (adjustment screws, cable connections, power switches, etc.) will be up front where I can see it (unless some physical constraint requires it to be somewhere else).

Build size: 10 inch cube (more or less).

Mechanism: core xy (considered delta, but decided I liked core xy better).

Project name: Jiggit.

Energy Transmission: GT2 belts (considered spectra line, but thought belts would be less finicky to adjust and maintain).

Motherboard: smoothieboard (smoothieware seems to have good support for core xy).

Structure: V-Slot Linear Rail (and wheels that ride in the slots).

Belt arrangement: Stacked belts (not crossed) with the belts running along the top of the X and Y rails (so I can see them). Something like this:

Not shown in that assembly, the motor will be at the front mounted upside down to get the drive gear close to the Y rail sort of like this (imagine the blue belt wrapping around the drive gear):

In the back end, two GT2 idlers will be stacked with a spacer between them (so they can rotate independently with no scraping) kind of like this:

The spacers for the pulleys actually gave me the most trouble since there isn't a very large radius fixed center portion in the pulleys I got. I finally contrived a ridiculous gadget I could use to drill out a 5mm hole in some brass M3 washers. It is a pain in the patoot, but it actually seems to work when I tried out the first 3 of them I made around some pulleys.

I can rotate each pulley independently, and the other doesn't try to rotate in sympathy. I don't feel or hear any scraping when I rotate them, and the motion seems smooth. So these look like the spacers I'll be using. They are only 0.5mm thick, so they don't add much to the belt separation.

Extruder: Direct drive bowden custom extruder (I suppose I could switch to a geared one if the direct drive doesn't work out, but lots of people have reported direct drive works fine).

Hot end: E3D v6 (perhaps someday I'll switch to a chimera or cyclops dual extruder, but a single extruder keeps complications down to start with).