I want to build a 1500 x 1500 Ox. I have sorted all the mechanicals out, including sourcing the Ox plates, but before I go and pull the pin, I have some questions: Is this a stupid idea? I have the room and would like the large build area so that isn't an issue. How is my y-axis going to fare with 2x 2060s over 1500mm? Using stock Openbuilds parts, is it possible to use a Nema23 stepper for the Z-axis? Is it even a good idea? My CAM experience to date has been with 3D printers, but my engineering and electronic and computer experience is of the 40+ years variety... which is why I am completely flummOxed over the electronics - so many choices, so many combinations. I live in the third world and electronic and engineering parts don't exist here - everything I need I have to import. Also, I am on a limited budget. I have a 24V 400W DC supply sitting spare. Is that going to be enough to power my creation, Or should I be looking at something 36V+? I know that a Gecko540 is the kit to have, but I don't have $700 spare, so that's out. I do have a couple of old Dell desktops and a nice Shuttle micro computer that I can use - but I also have about a hundred Arduino, a couple of Raspberry Pi and a couple of ARM M3 micros I can put to use. I suspect the Arduino just doesn't cut it at 8-bit and 16MHz, but the R'Pi and ARM are both 700MHz and the ARM has a decent amount of RAM - could they be used as dedicated motion controllers? And this is where I get bogged down. I can buy a package of steppers with drivers for under $100. But how do I tell them what to do? I've seen the TinyG, but it is a bit limited on power (2A) or am I kidding myself about how much power I will need? Primarily I will be cutting MDF and ply. Maybe I will look at carbon sheet and light alloy later on, but for now, it is just timber-based. Any advice gratefully received.
I've just built a 1500 x 1500 ox and the two 2o60 profile seem to stand up to the distance very well. I did make a modification to the gantries tho so they were more supported see this thread : http://www.openbuilds.com/threads/ox-max-build-with-mods.626/ As for a nema 23 for z you would need to make a different plate to mount it to. Tbh I can't see what you will gain out of using a bigger motor. I might be wrong but isn't the thread screw and anti backlash nut only efficient up to a certain speed?
Zootalaws, Our situations are similar (3D printing, computer experience, plethora of used hardware at hand, Arduinos and Raspberry Pis, etc), except that I'm not in the third world...or maybe Canada qualifies as third world now. But the shipping situation is similar here for many of the parts. If you have a spare Arduino, GRBL is probably a good place to start for a controller. My preference is for open source solutions, making this option attractive. The fact that the Shapeoko community prefers GRBL means that there is lots of expertise floating around out there. TinyG has my attention as well. Like you, I'm nervous about the limited current. However, I'm seeing the limit as 3A here. I would also like to use a Raspberry Pi for controlling the router. My experiences with Octopi and a RepRap were quite good. Being able to upload G-code through a web interface, then start and monitor a print remotely made 3D printing a much more enjoyable experience and drastically reduced my exposure to plastic fumes. I would like to do something similar with a CNC router. It turns out that a fork of Octoprint exists for exactly this purpose.
@Jonny Norris Great info, thanks. I don't think I am in a position to be able to make additional plates, until I make the machine, but then, it is a distinct possibility. Where to locate the router has been on my mind... I have a 9 x 5 workbench, but then I would lose my workbench. Given the price of hardwood timber, plywood and MDF here, I think I will have to build a custom table for it - and may as well start now, while waiting for all my parts to assemble @Rural thanks for that- I am also an Octopi user and saw the recent fork. So, Grbl and a decent set of drivers, an R'Pi and a bit of cable - could be the answer. I have been led (Pulled? Pushed?) to a Gecko G540, but I really can't afford one. And I hate that it's parallel. So many things to think of - now to find some low-impedance 270oz steppers...
GRBL, some beefy drivers, and a Pi is exactly what I've got on the slate for myself. If you find some decent drivers, shout about it here. I won't do parallel. Not that I have a really good reason, but I just can't do it.
The DRV8825s seem to have some grunt and they fit the 'Pololu' pattern, so can be used with quite a few shields. http://www.reprapdiscount.com/elect...gned-by-kliment-pololu-compatible-driver.html
