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[Solved] MMU always choosing 1st filament  

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John L
(@john-l)
Eminent Member
MMU always choosing 1st filament

I managed to do about thirty prints successfully...but today, it's now ignoring the filament selection I make in the slicer, as well as any attempts to change the filament before printing (either using buttons, or selecting 'unload filament' and answering '3' when it asks).

I had a look at the gcode that the slicer made, and it has a 'T0' - I changed that to 'T2'. No change. It still pulls from the first one.

Any idea what I could have accidentally changed ? It's driving me crazy.

Posted : 16/03/2021 5:38 pm
EJTH
 EJTH
(@ejth)
Eminent Member
RE: MMU always choosing 1st filament

Does your selector motor make any noise at all when you power the machine on? It should say a clicking noise. If not, and if it doesn't move at all, I think its something with your selector motor, maybe it is unplugged or the cable has been damaged somehow? I would first test that, just by powercycling the printer.

Posted : 16/03/2021 9:14 pm
EJTH
 EJTH
(@ejth)
Eminent Member
RE: MMU always choosing 1st filament

Sorry. That was kinda bad info, its the idler drum that makes the sound I suppose?!

Anyways... Does the motor move at all? Does the unit give an error? Or does it just go back to filament 1 each time you print?

Posted : 16/03/2021 9:21 pm
John L
(@john-l)
Eminent Member
Topic starter answered:
RE: MMU always choosing 1st filament

Well, it usually gives some error when I try print. Pressing 'test again' on the MMU, and it works fine. I assumed that was kinda normal, as it's rarely repeatable..it's different errors, at different points.

 Aaand...just there...yes. It asked me which filament I wanted to use, before printing. So it's printing with my choice for the first time today. WTF ? Maybe it's just haunted.

Posted : 16/03/2021 9:32 pm
EJTH
 EJTH
(@ejth)
Eminent Member
RE: MMU always choosing 1st filament

@john-l

if you just want to print with a single filament, and you want to choose it on the machine. The best way is to use the "MMU2s single" profile in slicer.

This will make the printer ask what color you want to print. Again, I would advise that you keep away from the button interface and only use it when the MMU2s is giving you errors.

I am actually not sure on the behaviour of the MMU2s if you just pick the normal prusa profile... I would assume that it just prints from whatever is loaded, but I am not sure, maybe it goes to tool 0?

This post was modified 3 years ago 2 times by EJTH
Posted : 16/03/2021 9:37 pm
John L
(@john-l)
Eminent Member
Topic starter answered:
RE: MMU always choosing 1st filament

I think I worked out what was going on. My Slicer was setup to handle an MMU. But Octoprint has a separate 'number of extruders' setting, so it was stripping out tool change gcode. Gah. I think this means if I move between multi-filament, and single-filament, in the slicer, I'll also have to update the setting in Octoprint too.

Posted : 28/03/2021 3:39 pm
K7ZPJ
(@k7zpj)
Reputable Member
RE: MMU always choosing 1st filament
Posted by: @john-l

I think I worked out what was going on. My Slicer was setup to handle an MMU. But Octoprint has a separate 'number of extruders' setting, so it was stripping out tool change gcode. Gah. I think this means if I move between multi-filament, and single-filament, in the slicer, I'll also have to update the setting in Octoprint too.

There is an Octoprint plug-in that prompts your for which filament to use when printing with the MMU2S Single setting in Prusa Slicer.

No configurations changes or gcodes modifications required after the setup of the plug-in.

Here is the documentation link: OctoPrint-Mmu2filamentselect

 

Posted : 28/03/2021 6:39 pm
Robin
(@robin)
Prominent Member
RE: MMU always choosing 1st filament

@john-l

No, you can keep OctoPrint configured with 5 extruders (shared hot end) and use MMU-Single mode in Prusaslicer. Without the plugin K7ZPJ mentioned the printer will ask which filament to use, with the plugin you can select it after the print is started via Ocoprint-UI.

If at first you don't succeed, skydiving is not for you.

Posted : 30/03/2021 6:28 pm
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