Just got a Cubex Duo from my local library. They are in a new location and didn't want to take this one with them as they have had problems getting consistent prints from them. And I can understand why after spending a week with it. All the filament they had was brittle, worn and some was 5+ years old.
Anyways, the hardware itself (printer) seems to work alright. All the motors function, extruders... extrude and the hotends melt. The print quality is no where near as good as my CR-10 but that is not why I bought this printer. Mainly for a toy to convert/play with and see how good I can make it.
I've been reading a few sites (thingiverse, RepRapWiki) and whatnot on the conversion to Open-Source but still have a few questions on the approach.
I agree that the printer needs to have a heated bet to really be of any good for materials like ABS or PETG; what type of 300mm x 300mm board would be a good fit for this machine? I can modify the existing bed but I do have a friend with a plasma CNC cutter that could make a new sledge if I asked him to i'm sure. Not sure what the best approach would be.
I know I will be ditching the 3D systems hotends for a set of V6 clones; but was wondering if there is also enough room/mounting option available for maybe the Titan extruder as well? I'm only wondering because the nominal filament diameter from Cubex is 1.7mm; and wasn't sure how well the extruders would hold up over time with normal filament diameters (1.75 +/- 0.03 typically).
And I see most people are using a 24V power supply. will the motors work fine at 24V or do I need to step them down? I've been debating on using an MKS 1.4 based board as the brains and I believe it has a pin to step down the voltage if necessary. Or is going 12V an option? Wasn't too sure if 24V was required because of the Nema23 Z motor.
I bough a Cubex Trio from a frustrated owner (who had clogged the nozzles for the "last time") for only $400 CAD. I thought -- hey this printer was originally $4,000 and looks like a battleship in terms of build quality.
Cleaned the nozzles only to discover -- this printer prints like shit. The stock hot ends of a Cubex are insane, the first thing I did was throw them in the garbage, they are truly crap. However, with some TLC I was able to turn this machine back into an excellent workhorse.
The stock extruder motor and gears surprised me. With the original hot end they kept slipping... I was going to replace them with another motor/extruder gear until i made the E3D holder from this design -- https://www.thingiverse.com/thing:1239945
Turned out that E3D's are the most important step to make this shit printer into gold.
I bought a modern Rumba board, some micro stepping drivers, and initially loaded it with the firmware from https://reprap.org/wiki/Cubex_to_RepRap_Conversion project which unfortunately is a really old version of Marlin 1.0.2
I removed everything down to one extruder, thinking that weight was the main issue.
And it worked -- bang, all of a sudden the prints were MUCH better, better hot-end, no more clogs. To my surprise even though I printed the hot-end bracket out of PLA, the cooling fan is so good and any cheap $10-15 E3D hot-end is so stable, that I ended up with a rock-solid hot-end.
The only problem? The firmware has the Y stop set to Y-MIN instead of Y-MAX and the Y stepper motor direction is reversed. This resulted in prints that printed mirrored.
Easy fix -- just change it in Marlin the stepper direction from -1 to 1 and use the Y-MAX as endstop, change CURA so it knows that 0,0 is in the FRONT of the printer, after allowing it to HOME in the LEFT BACK... and you've got a stable printer.
Next, I upgraded Marlin to 1.1.7 ( a lot of defines changed names!) to try to install a BLTOUCH probe for better Z axis control, but had some issues so I left a home-made Z end stop in place for the moment. The new version printed even better than the first, all of a sudden all ringing disappeared.
So, for fun I jacked it up to 100mm/sec, and only then could i begin to see the ringing I was getting back in the "old days" of 60mm/sec and Marlin 1.0.2
Not sure exactly what changed in Marlin 1.1.7, perhaps the micro-stepping control, but prints are gorgeous, extruder missed steps have disappeared, ringing gone.
Next up on my list -- convert it back to 2 nozzles, as I've discovered that the machine seems more balanced with two weighted stepper motors on board, and I don't really see much difference with one or two stepper motors.
I know many people have said this printer needs to be a Bowden in order to print well, I'm not finding that to be true, I found getting you're Jerk and acceleration settings in a good zone is enough to have a printer thats currently out-performing my heavily modded Wanhao i3.
For fun I printed a Herringbone gear spinner on it and first one welded together on the first layer, second time through I got smarted and turned on the fan on the first layer.
Oh one other mod -- I used a SSR relay to control a 12 x 12 heated build plate that plugs in straight from the AC and uses a 100K thermistor. I strongly suggest you spend $15 on a GOOD relay and the $40-60 on a good heated plate.