Hi folks, (relatively new here - just know enough to be dangerous) I've scored what's essentially an OpenBuilds OX. It's functional, but needs a rebuild & some TLC. Major parts still in great condition (router, motors, etc), others replacing (belts). It's rocking a Geckodrive G540 with a SmoothStepper (USS). I'm not extatic re the USS, as I feel it limits my options (especially when I need to poke in the guts during rebuild), as I can effectivly only use it with Mach3 & does play with the rest of the stack I hope to try/use: LinuxCNC, CNCjs, etc. For now I'll talk directly to the GeckoDrive via DB25 form the host PC, but exentually I'll need to tidy & tighten things up - especially around the general safety aspects - so will need to find a suitable substitution to the USS. I've been hoarding a whole swathe of SBC's - Arduino's of all sorts, BBB's, RPi's, ESP's, RAMPS, etc - that would be good fits for this need, although I'll need to find a suitable solution to talk realtime-parralel dot he driver. grblHAL (or vanilla GRBL) seem the way to go, as most of the rest of the stack seems to default to GRML as the lowest-common-denominator defacto standard. Since I've not quite crossed the threshold here, I'm as the limits of my knowledge. I've flashed enough board to know I need to have all my ducks in a row before comitting to flashing or otherwise mess with embedded systems. What is my best course of action here? I feel I should pop grblHAL on something like a RPi, RAMPS, Mega or ESP, but then that assumes the control & driving happens on the same board, whereas I want to use the GeckoDrive for the Nema's, but that required the controller board to talk over DB25. The numberous IO's on a Mega makes it well-suited for other safety considerations, such as end-stops & kill-switches. Is both the Gecko & Mega connected to the PC, or is there a more elegant way for me to achieve this outcome? I need to use what I have on-hand: imports are difficult at present, and I've already spent more than I can affort right now just to get this machine. (a stretch-goal for me is to incorporate MQTT for monitoring & logging)
Sounds like fun. I'll be interested to see how it turns out. I started out with a XPROv3 controller, and quickly found the driver chips to be unable to drive NEMA23 motors. Ended up purchasing the BlackBox controller. The XYZ Probe Plus is an awesome little add on for that controller!!! Good luck!
The USS is probably the biggest SPoF. Don't think it was even wired in completely. This machine is a bit of an odd duck: sports a decent number of mod-cons, but other choices are weird, such as the choice of a belt-drive as opposed to lead-screw for a machine this size & the expected torque. Has dust-shoes but no extractor.... All in all it has the makings of a capable machine, but I can't afford to (NZ-locally) spend much more than I already have, or at least not until it's earned its keep before further upgrades.
I don't know if I just found the answer to my own problem... The beauty of Open Source is that, well... things are Open! The Gecko's DB25 pin-out is known, and so is GRBL on Mega. In theory I should just be able to map one to the other, after checking polarity & ratings & whatnot. Almost seems too simple... (/me needs to do more RTFM)
yeah, open source is a cool thing sometimes! sometimes can be frustrating, but that's all part of the learning. well i do hope you have success. the belt drives will get you there, just don't push it too hard, as i've heard there can be stretch on occasion. i designed and built my own using lead screws. it's about the same as a lead 1010 from openbuilds, except i used c beam instead of standard 20x80 vslot for the z axis uprights. there are a couple of differences in how i mounted things, but other than that, that's pretty much what i have. once i get this earning it's keep, my first upgrade will be a vfd spindle. i've already had to change brushes in my dewalt router with only 30 days on it. keep us posted. i don't know much about the controllers you have, so i can't speak to those, but i'll be interested in hearing about your progress. i find this stuff absolutely cool and fascinating!
belts are fine on bigger machines, pull them to 12kg force with a fishing spring balance. more if you can prove you have a tension problem, but make them all the same. I would go with an Arduino Uno running stock GRBL, which you can install using OpenBuildsCONTROL (software tab at top of this screen). Read the GRBL wiki, all of it.Home ยท gnea/grbl Wiki Watch the OX construction videos, yes, all of them (-:
Best thing for a belt machine is to dual belt them, makes a huge difference, I haven't had to touch my belts in 2 years. I didn't use double sided tape as Martin did, I used .5mm x5mm wide carbon fiber strips glued with CA in the channel and the belt glued on top of them to make up the gap, held up great. CA glue holds more permanently than the tape (especially glue made for rc truck tires). Cheers Gary
