Dry Box with Integral Rewinder

The purpose of this design is to create a moisture free storage container for spools of filaments that are loaded and available for selection by Prusa's MMU2 accessory.

This design incorporates and modifies two existing designs:

• Integrated Auto-Rewind Spool Holder by VincentGroenhuis and
• Filament Spool Stand for Rubbermaid Container by MysteryDough

This design supports wider spools compared to the external rewinder version (https://www.thingiverse.com/thing:3729929).

The containers sit on the top of an enclosure, such as the one referenced below, and feed filament into a PTFE tube that connects to one of the MMU2 input ports. The filament container or Dry Box contains packets of desiccant that absorb any humidity that does infiltrate the container. Except for a very short piece of filament that is within the MMU2 feeder, no part of the filament is exposed to the surrounding atmosphere.

Also incorporated in this design is the Integral Auto Rewind mechanism that applies rotational pressure in opposite direction to unspooling motion. This re-spools the extra filament that is returned to the container upon Prusa i3 MMU2 filament Unload or Eject.

Included in the file section is an OpenSCAD file that can be used to generate rewinders of different sizes. As a matter of convenience all the parts necessary to assemble a 87mm wide spool are included in the file section of this design..

Note:
It is imperative that the unspooling motion tighten the Springs and not loosen them as the later will break one or more of the Springs. To this end, the Cap must be placed on the left side (looking Forward with the PTFE tub closest to the observer) of the spool for filaments that are unspooled from the top of the spool.

Typical Enclosure: https://www.thingiverse.com/thing:2396990