Toolboard for extra steppers to control multicolour setup

vistalert

I've been watching @deckingman on YouTube with interest. Thanks for the awesome content and contribution to the community.

I'm inspired to build my own 4 colour system, and to get started I thought I'd buy:

https://www.duet3d.com/Duet3Expansion3HC
...and a couple of these dual hot ends as an experiment.
https://www.ebay.com.au/itm/V6-Hotend-Dual-Head-Extruder-0-2-0-4-0-6mm-Nozzle-12V-24V-1-75mm-Filament-fan/223587552825?var=522737141104

I was thinking to add just run of the mill steppers, extruders with bowden tubes, to avoid adding weight on the gantry.

So my questions are: Does this sound sensible? I think it does based on @deckingman video as a guide to the concept.

Would I get the 3HX and then just configure each "colour" as a separate tool, and have a nozzle offset for each of the four hotends?

Welcome your thoughts, advice and insights!

Chris

deckingman

@vistalert
First off, a quick description of what a tool is, because that's what you'll have - 4 tools. Essentially a tool consists of an extruder, a heater and a temperature sensor. There is also usually a heat sink cooling fan but this is associated with a heater/temperature sensor so it's not strictly part of a tool. Optionally there will be a part cooling fan and you'll likely have one per tool.

So you need to connect 4 heaters, 4 temperature sensors, 4 hot end cooling fans, 4 extruder motors and optionally up to 4 part cooling fans (you could maybe use one fan per pair of hot ends (tools)). There are also things like end stop switches and/or Z probes to think about.

You've got a couple of options - either the expansion board or what might be a better option would be to use tool boards for each extruder. It all depends on where you plan to mount the extruders. If you use a single expansion board, then you'll need to connect one tool (heater, temp sensor, heat sink fan and extruder motor) to the main board and the other 3 tools to the expansion board. So all the wiring will go to either of two central points (the main board or the expansion board).

What might work better would be to use tool boards instead of the expansion board. That would allow you to mount each tool board close to each extruder for example. Of course you'll still need to run wires from each tool board to each heater/temp sensor/fan etc. Alternatively, you could mount tool boards on the carriage. This would make wiring the heaters, sensor,fans etc a lot easier and neater but of course, you then have longer runs of cable from the tool boards to the extruders motors. Having tool boards on the carriage might also simplify connecting a Z probe but check the list of firmware limitation here https://duet3d.dozuki.com/Wiki/Duet_3_firmware_configuration_limitations

Actually, there is a third option which is to use Duet 2. So you'd need the Duet Ethernet or Wi-Fi plus the Duex5. But in this case, all the wiring has to go back to a central point because the Duex5 has to be very close to the main board.

Edit. I've only recently started to use YouTube more. There is a lot more stuff in my blog if you haven't already seen that (link n my signature).