Prusa MMU2 filament rewind guide

thingiverse

This solution to the filament rewind / buffer issue with the MMU2 is remarkably straightforward, utilizing an empty capture spool positioned between the actual filament spool and the MMU2. Rewind systems employing springs or weights have a reported drawback: they can tug the filament out of its MMU2 pre-loaded position. This solution does not have this problem. I prefer to set up my system vertically, as seen in the photos, but it should work just as well horizontally. A simple PLA guide is attached to the vertical wall beneath the capture spool to hold the 4mm PTFE tube at the optimal angle for storing slack filament on the capture spool. I used a strip of Velcro glued and stapled onto the wood wall to secure them in this position. The filament is first wound with three or four loops around the capture spool. The guides can be easily removed to assist with loading and aiming the MMU2. A 4mm nut & bolt can be used to clamp the PTFE tube tighter, ensuring a secure fit. The actual capture spools in the photos were custom-made by me since I didn't have enough empty spools available. They are 30mm internal width, but I don't think this will make a difference when using empty spools. Please note that it's essential to use +50% infill for added strength. Good luck with your project! Graham