My plan is to stick fairly closely to spauda01's design. At least, I plan on making it the same dimensions, with the cantilevered z-axis, and with the 200x300 PCB bed. The hot end will be a E3D V6, and I'll probably move the BL-Touch over from my Prusa clone.
I cut the OpenBuilds v-slot aluminum extrusion with my chop saw using a cheap framing blade and lubricating with cutting oil. A couple of pieces had a bit of a burr, but nothing a deburring tool couldn't easily remove. It's hard to imagine a non-ferrous blade would do significantly better. Tapping the M5 screw holes went smoothly too. The recommended extrusion has holes sized correctly for an M5 tap so it's easy to keep everything straight.
ABS or PETG are recommended, but my current system isn't ideal for either. A bunch of folks are having success with PLA, so I'm starting with that. I'll probably re-print spares for the structural parts out of another material when the machine is up and running. I have some parts coming from China, so I have a few weeks to get things printed.
For the most part, the printing on my prusa clone has gone smoothly. Then, I decided to let it run unattended for a couple hours and there were issues. I'm guessing that a stray bit of plastic caught the E3D's silicone sock and moved it so the remaining filament extruded inside it.
Getting the bearings, washers, and nuts in place on the right and left rear idlers was easier than I expected. Bent tweezers work well for setting the bearings and washers in place. The nut seems like it might be harder because it can side further back in the hole than it needs to go. I started by running a deburring tool around the edge of the pocket so the nut could slide in easily, then turned the assembly upside down and pushed the nut back until it was in the right place.
Bent tweezers are also a great tool to hold square nuts in place when inserting a screw from the top. Sliding the tweezers under the nut will force it up against the top of the channel. Otherwise it may be hard to pick up the thread or easy to cross-thread the nut.
While it's sometimes possible to get square nuts into the slot from the top without sliding them down from an open end, the tolerance is tight and some nuts just won't fit. Also, unless you are screwing directly up or down, holding the square nut in place is a pain. Having a handful of drop nuts is much less frustrating.
In a departure from the "stock" D-bot, I'll be using a Smoothieboard for control and OpenBuilds' NEMA 17 steppers. While the machine would work with a clone RAMPS board and lower torque steppers, the Smoothieboard is very well designed and has a lot of room to grow if I decide to try new things. It takes up more space than the RAMPS board, so I'll have to think about how to position it, but there are a lot of options.
Rob's D-Bot Build
The plan is to make this a fairly stock D-Bot build. We'll see if mods start creeping in.
- Build License:
- CC - Attribution - CC BY