RepRapFirmware Dual Z support (software)

Does RepRapFirmware have the ability to use the second extruder as a Z2 like in Marlin?

Not yet. I have yet to hear of a system in which it is not possible to run the two or three Z motors in series from a single driver, although if three motors are used then 24V power may be advisable.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

The Robo R1+ uses separate drivers for both Z-Motors but I think they do it using a special RAMPS board that jumpers step/dir from Z to E1.

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dc42
Not yet. I have yet to hear of a system in which it is not possible to run the two or three Z motors in series from a single driver, although if three motors are used then 24V power may be advisable.

I'm thinking of using 3 Z axis lead screws for the printer I'm planning with a view to eventually implementing auto bed levelling at some point in the future when you get around to it. So, to start with I'd like to wire them in series. Can you point me to a wiring diagram or schematic? Also, I'm thinking of have the motors bottom mounted but don't much like the idea of using the motors as thrust bearings. So, I was thinking of supporting the screws in their own bearing blocks with either tapered bearings or a thrust bearing/radial bearing combination and then using a belt and pulley arrangement between the motor and screw. While I'm at it, I was considering using a 2:1 ratio to give me back the resolution I'd lose from lead screw vs threaded rod. So with this gearing, would you still recommend 24v power? On the same lines and as it's gong to be quite a large printer, do you think I should just go for 24V in any case? Are there any downsides? Sorry for so many questions.

Here's a diagram showing how to connect two stepper motors in series. It's easy to extend to 3 or more motors.



I recommend using 24V power for all printers except small ones. The main advantage is that you can drive double the bed heating power from a Duet before you need to use an SSR. Using 24V also maintains motor torque up to higher speeds. The only real downside is that 24V fans are not as widely available as 12V fans. But unless you are looking for something out of the ordinary, you should have no problem getting 24V fans.

Edited 1 time(s). Last edit at 05/26/2016 04:58PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Sounds good. Actually I do have some tiny 30mm centrifugal blowers that I'm planning to use close to the nozzle for print cooling, which I doubt if I'll find in 24v versions. I guess there is nothing to stop me using a 24v to 12v DC converter just for the fans right?

a DC/DC converter is low cost, but you also can use 5V fans. On my D-Box, I use both and in fact I set the DC/DC converter at 10V to reduce noise (for filter recycling fan and board cooling fan). I use 5V for hotend controlled and fixed fans (Sunon), as original 24V hotend fan died.

See here [reprap.org]

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Pierre

- Safety [reprap.org]
- Embedded help system for Duet and RepRap Firmware [forums.reprap.org]
- Enclosed delta printers Lily [rouzeau.net] and Lily Big [rouzeau.net]
- OpenScad delta printer simulator [github.com]
- 3D printing on my site [www.rouzeau.net]

Thanks for the tip. My other thought was that as I'll be using 2 print cooling fans, one either side of the nozzle, to just wire them up in series and run the pair off 24v? Or is that a bad idea?

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deckingman
Thanks for the tip. My other thought was that as I'll be using 2 print cooling fans, one either side of the nozzle, to just wire them up in series and run the pair off 24v? Or is that a bad idea?

e

Thats what i'm doing. No problems

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critical_limit

Quote
deckingman
Thanks for the tip. My other thought was that as I'll be using 2 print cooling fans, one either side of the nozzle, to just wire them up in series and run the pair off 24v? Or is that a bad idea?

e

Thats what i'm doing. No problems

Thankyou.