Filament spilling out of the cassette. - Assembly and first prints troubleshooting https://forum.prusa3d.com/forum/original-prusa-i3-mmu3-assembly-and-first-prints-troubleshooting/filament-spilling-out-of-the-cassette/ Prusa3D Forum Discussion Board en-US Wed, 17 Jun 2026 16:02:49 +0000 wpForo 60 Filament spilling out of the cassette. https://forum.prusa3d.com/forum/original-prusa-i3-mmu3-assembly-and-first-prints-troubleshooting/filament-spilling-out-of-the-cassette/#post-756786 Tue, 08 Jul 2025 12:33:15 +0000 Hello, I'm very new to 3D printing and recently got a Prusa MK4S with the MMU3. I asked for it come come assembled so I just did minimum assembly myself. One of the things was the spools and cassette for the filaments, and everyting is working just fine, it's printing fine etc.

 

The only think I'm not sure about, is that every time, during a print, the MMU changes filament, the filament that is removed spills out of the cassette which is causing the filaments to tangle, resulting in me having to babysit every print so the filaments don't tangle when they're being loaded back into the MMU.

Please see the image attached showing how it ends up looking.

It's like the MMU is pushing out far too much filament resulting on the spill. If anyone could give me a tip on how to avoid this, I would be very grateful. 

Thank you.

 

]]> Assembly and first prints troubleshooting CissaRegoDMAG https://forum.prusa3d.com/forum/original-prusa-i3-mmu3-assembly-and-first-prints-troubleshooting/filament-spilling-out-of-the-cassette/#post-756786