Spool Holder with cage for filament buffer.

Story (Skip if you have no interest)

I was working on adding 3D Chameleon to my printer, and I encountered a problem with filament entanglement when unloading. After researching, I found that I either need an auto-unwinding spool holder or a filament buffer.

I found many auto-unwinding spool holder designs. However, because the filament in my Qidi X-Max 3 unwinds along a long path, I need a lot of revs, and the energy stored could over-unload the filament when the 3D Chameleon is not clamping on it. So, a filament buffer is a better fit for me.

However, one big problem with filament buffers is they consume a lot of space. Then I found the "Minimalist Spool Buffer", a very clever design. 

To make it fit my personal needs and preferences. I remixed it.

• Fit most of the 200mm diameter 1KG filament spools
• They are max 8mm wide so that I can put two of them into an Ikea 365+ 10.6L food container
• Able to use with and without the dry box

Additional components needed:

• 2 x 608 Bearing
• 1 x Spool adaptor (https://www.printables.com/model/1190667-universal-spool-adapter-50-75mm)

Printing

• No support needed
• Print as oriented in the STL files
• PLA, 0.4mm nozzle, 0.2mm layer height work fine
• You need at least 12 “frame nuts". But I recommend 24 to make the assemble sturdy.

Assembling

• Assemble as shown in pictures
• Adjust the nuts to balance friction and the gaps between the spool and the cage.

• Instead of clipping sticks to create a filament buffer cage, I use threaded rods and nuts, which allow me to adjust size precisely to:
  • Optimize friction between the spool and the cage.
  • Minimize the gap between the cage and the spool to avoid filament getting into the gap during unwind and rewind.
• Added a base such that it can be used alone without a hanger.