Filament load/unload issues? MMU2 taking too much space? Not with this Sisyphus Auto-Rewind spool holder! It keeps filament on the spool during unloading, up to almost three revolutions.
Use two curved nuts to attach the spool to the roller. Put roller on stand. Insert filament in extruder/MMU2. That's all!
A filament tube can be installed from extruder/MMU2 to the frame in two ways: above (using tube holder) or below the spool.
The slope of the track can be adjusted by placing objects under the frame and/or by screwing two M3 bolts in the designated holes in the frames. This has a direct influence on the rewinding torque.
This design is inspired on the circular and linear gravity-based spool rewinders. Instead of lifting up an external weight, the Sisyphus rewinder lifts the whole spool by rolling it up an incline.
Like all gravity-based rewinders Sisyphus makes a clicking sound when the end of the track is reached. This noise can be dampened by using rubber feet under the stand, or eliminated altogether by applying the clutch mod.
Sisyphus (or Sisyphos, Σίσυφος in Ancient Greek) was the name of a naughty king who provoked the wrath of the gods. Among others he betrayed Death himself, even imprisoning him when he got the chance. Eventually he was punished by the gods and placed in the Underworld, where he was forced to roll a giant spool up a steep hill which would always roll back, repeating itself until eternity.
Other gravity-based rewinders and community mods:
Circular Gravity-based Auto-Rewind Spool Holder
Linear Gravity-based Auto-Rewind Spool Holder
Prusa i3 top mount roller-style gravity rewinder
Sisyphus Clutch Mod
Cormer Mounting Clip For Lack emclosure
July 12, 2019: First version (v4.0) released
Aug 4, 2019: Discoved that an older file of the frame STL was originally uploaded. Frame_v4.0a.STL is the same version as in the zip file and is more reliable than the older one.
Prusament / Colorfabb PLA
Prusament Mystic Green / Colorfabb Intense Green
Curved nuts and tube holder are identical to those in the Universal Auto-Rewind Spool Holder.
The ZIP file contains single-material, multi-material, STEP, full build plate versions and GCode.
If you like the different colors but do not have a multi-material printer, then you could throw in some manual color changes in the bottom few millimetres for a comparable result.