Multi color printing with Prusa's MMU V2 & Duet?
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@phaedrux said in Multi color printing with Prusa's MMU V2 & Duet?:
@fma I think part of the multi color precision of the v2 comes from being direct drive versus bowden. So there's that.
My suggestion does not change that point: the MMU is still used to load/unload filament, extruder remaining on the printer carriage. But instead of having the moving selector, and only 1 PTFE tube, there is n PTFE tubes, and a splitter n-to-1 above the extruder.
Even so, conditional gcode is being hinted at for the near future, so maybe it won't be long to wait.
That's good news!
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Firmware for the MMU board has been published, as also the schematics of the board.
Looking at the slic3r profiles, there is a 'ramming' function. Apparantly this is to retract filament with a clean cone and no strings to avoid jamming.
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Great!
Does anyone understand how 'ramming' params work?
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Regarding conditionals, couldn't something like this be used with the filament sensor of the MMU: https://reprap.org/wiki/G-code#M226:_Wait_for_pin_state
or: https://reprap.org/wiki/G-code#M577:_Wait_until_endstop_is_triggered
or: https://reprap.org/wiki/G-code#M583:_Wait_for_pin -
Yes, but what if the input is never triggered?
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@fma why would the sensor not be triggered?
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If case the filament does not engage correctly in the carriage, because of melted end (blob).
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I guess that's why 'ramming' needs to be tuned properly.
Anyway, with those available gcodes should it not be possible to write some custom macro's?
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Yes, sure! This is simple motors, so a couple of G1 commands should do the job. And the carriage needs to be homed.
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I don't see any homing switches so I guess it relies on sensorless homing
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Right. It uses TMC drivers...
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If it uses sensorless homing normally, wouldn't installing a normal endstop switch correct for that issue?
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Yes, sure. And it should be easy to do.
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I was hoping to pick up the MMU2 to put on a custom printer with a Duet 2 board.
Is this something anyone has already accomplished or would it be supported by Duet at any point in time?Or is this only a home grown venture?
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@oliman I was going to. Awaiting a bit more reviews on the MMU2 and maybe the first design iterations.
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Thanks @bartolomeus, I'll keep an eye out on reviews but I think I'm convinced the MMU 2 will be better than the Palette+. At least the design principles of the MMU 2 seem more dependable (also I'm not a fan of the custom Palette+ splicer).
Anyways, maybe someone will come out with a more mod friendly or printer independent MMU 2 clone. I would rather support Prusa, but not at the expense of taking a gamble of the MMU 2 not working with a non-Prusa printer.
I'm sure someone smarter than me will figure it out soon.
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For sure, MMU2 seems more reliable, and easier/cheaper to fix if it brakes. And interfacing it with the Duet/Duex is easy if you remove the electronic, and wire motors to the Duet. Then it is just a matter of a few G-Codes as macros to use it. Maybe ask Prusa if they can sell it without the electronic?
BTW, I'm working on my own filament multiplexer, but a mix between v1 and v2: a passive mux above the extruder, like in the v1, but a simple loader, not Bowden, like in v2. I'm waiting for mini-clutch to test my design.
Frédéric
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Someone is already designing an alternative. The design is on thingiverse. He also has a thread on this forum somewhere,
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In fact, there are 2 designs on Thingiverse (both guys are on this forum). I started mine because it is different in many ways...
Frédéric
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@fma Do you really think it would be easier without MMU v2 electronics? I think it should be possible to send the code to change the filament. But it is true you would need to change Duet FW to support this.
I really hope it will go this way.
