Rumba controller board

Hi all,

I am very new to the RepRap community and have a couple of questions relating to a conversion I am trying to complete.

I am one of the unfortunate ones that purchased a Cubex Duo 5 years ago - I say this as a lot of people have given it bad reviews and with some just cause.
Over the past 5 years, I have changed over the software and completed many over mods to make the printer better and with great results but this machine has now died, both heads and main board now scrap.

So reading lots on these conversions I have started down the path of new electronics including a Hotbed.

I have purchased a Rumba board and 6x A4988 drivers and from what I have read my main problem is split into two questions;

1) The Z axis has a Nema 23 - 2.2v - 3.0A stepper and the A4988 can only drive up to 2.0A. Can anyone give me any suggestions for this problem (DRV8825 ?) or have they done this conversion?

2) The Y axis has a twin drive - Nema 17 - 2.8v - 1.68A steppers.
After looking around someone suggested stacking two A4988 drivers but I have found an expansion board (stepper driver extender A4988 DRV8825 extension stepper driver panel additional motor adapter breakout board drive expander).
From what I can make out this board would allow me to run two drivers simultaneously, one for each stepper.
Would this be correct or has anyone tried one of these?

Any help would be most appreciated.

The RUMBAs six driver slots make it easy to configure a second driver for an axis. In most firmwares you just have to enable this for the specific axis and select which driver slot serves the second motor.
In Repetier look for FEATURE_TWO_YSTEPPER
In Marlin look for Y_DUAL_STEPPER_DRIVERS

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

Thanks for that.

I take it as I will not be using 3 extruders I could use Extruder output 3 as the second driver.

Thanks again.

The NEMA 23 should only require about 600ma current if driven @12V. If you set the current limit on the DRV8825 for 2 amps you will burn up the stepper and the driver.
As far as the NEMA 17's they should only require about 400ma @ 12 V

the 3 amp rating on the NEMA 23 is for 2.2V not 12V. Steppers are usually driven an higher voltages than the rated voltage.

I always calculate the ballpark current using P (watts) = I (Amps) X E (Volts)

The NEMA 23 comes out to (2.2 X 3.0) = 6.6 Watts and (6.6/12) = .550 Amps
The NEMA 17 comes out to (2.8 X 1.68) = 4.7 Watts and 4.7/12) = .391 Amps

2 NEMA 23's on the same driver would be about 1.2 Amps ( I would 1 drivers for each NEMA 23) The DRV8825 will start to run a little on the hot side at 1.2 to 1.5 Amps if you drive 2 steppers from1 driver.

However the DRV8825 will easily handle 2 NEMA 17's

The current at 12V is just to get you close, in practice the current may have to tweaked a little higher to compensate for losses.

Hello I am also very new to 3D Printing and could really need some help. I am trying to convert my Cubex(1Printhead). I bought the following Material:

3D Drucker Teile Titan V6 Bowden Extruder Voll Kits mit NEMA 17 Stepper Motor Für 1,75mm/3mm e3D V6 Makerbot 3D drucker.

Rampen 1,4 Kit Mega 2560 R3 für arduino + RAMPS 1,4 Controller + 5 stücke A4988 Stepper Fahrer Modul + PCB Heatbed MK2B 3D Drucker kit.

My questions so far:
1)can I use the two Y motors paralel(one normal, the other one +-swapped)?
2)Is there a difference between the romba board and the raps i have got(because both use malin)?
3) is there a malin config i can use?
4) do i need to replace any ohter hardware?

I hope someone can help me.

Rumba is a an old Atmega based board, the RAPS is a 32 bit board. Marlin is used on a large variety of platforms, 32 bit is supported since V2. Chances are you will have to specify your own Marlin configuration for your printer.

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

Is here somewhere a pre configured Marlin for the Cubex to download? And ist it an good idea to use the magnetic end stops for X and Y axis and to replace the Z witch a mechanical one?

Hi, folks. After a long hiatus from my 3d printer issues I've decided to continue with my CubeX Trio. I need to go out for a while, but there are a bunch of older threads and posts for the CubeX printers.
Mine is working with one extruder and the Rumba+. I'll post my stuff and/or links later today. I dumped all three factory extruders and machined some J6 hardware to fit the original carriage, yanked ALL of the factory electronics
and only used the original wiring to the motors and carriage. I had planned on using all three extruders so I didn't drive the two Y motors with two drivers but instead wired the Y motors serially and, surprisingly, that worked, for now.
Installed a larger heated bed, too. I also replace some of the magnetic endstop switches with both mechanical and optical switches. No particular reason for doing that other than I had the switches sitting in front of me.

Although all of this is likely to work satisfactorily, the results from the 32bit boards appear to be more impressive. I have the ST 3D printer eval board with an STM32 that I'd like to make work. Same number of motor and extruder
drivers as the Rumba+ so to use all three extruders along with the double Y motor setup I'd like to drive the two motors with a Gecko higher amp driver. Might work with the G250X but don't know yet. I also have most of the parts
to drive the Y axis with one larger stepper but I haven't decided on the best way to do that, yet. More to come.

This may be useful, too, if you haven't seen it yet: [reprap.org]

tjm

Edited 6 time(s). Last edit at 10/17/2019 05:25PM by TJM3D.