MMU Single Buffer Unit SBU

During my MMU upgrade journey, I found the buffer system to be the one thing that made my MMU unusable.  Since I placed all my spools inside the enclosure to take advantage of the active drying, the RMU had to much tension and made you open the hole unit to just change on spool and the Prusa buffer was too bulky.  This led me to fabricate the Single Buffer Unit (SBU).  

The MMU3 redesign was a HUGE improvement to the original buffer and so much easier to load.  Though it works really well out side the enclosure, when placed inside it becomes to bulky.  After looking on youtube and figuring out on-shape (I love this website), I decided that I would make use of the side walls to use a single buffer wheel from the new MMU.  

To start, I used Ludvig Broome's spool holders (number 2 & 3) as a reference point to place the SBUs.  Since his holders are different sizes, I printed each one twice and I am still coming up with one for the very back for the fifth spool. (will be out very soon).
https://www.printables.com/model/338523-cobra-system-for-original-prusa-enclosure/files

Required hardware:

8 - M3 x 12 Screws
8 - M3 x 20 Screws
16 - M3 Nuts

4 - MMU3 complete buffer wheels from https://www.printables.com/model/531604/files

For easier access to the insides from the outsides, I did Eli's side mode. https://www.printables.com/model/545800-side-doors-sheets-and-supports

Print instructions

• Print settings: 0.20mm QUALITY
• Filament: PETG (tested on Prusament and Polymaker)
• 15% Grid infill

Each SBU is printed without supports though may need some on the screw hole cut out where the two pieces of frame mate together. The models do use a sacrificial layer if you are fine with bridges.

The screw holes do not need supports as they take advantage of the bridging hole method.