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printer or MMU2S is scraping off filament  

printer or MMU2S is scraping off filament

Hi All,

Im not able to finish multi color prints at the moment,
every print fails because of clogged extruder/tube etc.

after a couple of layers, the extruder/bowden tube is clogged, any idea what produces this kind of ultra thin filament scraps ?

Posted : 07/01/2023 4:50 pm
Noble Member
RE: printer or MMU2S is scraping off filament

What filament and temperature and does this happen when not printing with the mmu

Please help me out by downloading a model it's free and easy but really helps me out

Posted : 07/01/2023 10:27 pm
Topic starter answered:
RE: printer or MMU2S is scraping off filament

I've seen this issue with Colorfabb and Eryone PLA, printing at 205/60 (prusa slicer default). Before installing the MMU2S, I have not had this issue.

Posted : 07/01/2023 11:58 pm
Honorable Member
RE: printer or MMU2S is scraping off filament

I’ve had wet filament give odd tips and by ‘whisky’, but never anything like that…. Like some of the molten plastic is stuck in the nozzle and the retraction is ‘pulling’ a fine fiber?  Weird.

Posted : 09/01/2023 6:07 am
Prominent Member
RE: printer or MMU2S is scraping off filament

How do your filament tips look like when pulling filament back during colour change? Nice and clean or stringy? If your tube is clogging and you pull out strings like the one above out of it, I would guess it is the latter. 

Stringy tips need to be avoided if you want to have intervention free prints with the MMU. Stringiness depends on the filament type, brand and even colour but it can be made much worse by wet filament. It can't hurt to properly dry your filaments before printing. If that doesn't help, one can try out alternative ramming settings. There are some posted here on the forum somewhere ... not sure anymore where exactly. 

Generally some brands work better with the MMU than others. 

Mk3s MMU2s, Voron 0.1, Voron 2.4

Posted : 09/01/2023 9:07 am