Rack mounted spool storage and MMU feeder system

I wasn't satisfied with the messy and inefficient MMU3 spool setup that Prusa conceived of. Since my printers are on steel storage rack shelfs, it also means i have more storage space options available to me that do not take up as much shelf space. The solution i came up with is a number of simple brackets that takes a few lengths of 1" EMT (which is 1-1/8" OF, or 29.5mm OD). Where I am in the US, a 10 feet length is about $15; make the rack as narrow or as wide as you prefer, in my case it ended up being two 42" inch lengths of tubing, with four brackets (which is probably overkill, three would definitely have been enough).

The brackets are mounted on the shelf with M5 bolts and nuts that go through the shelving (drill a 5mm hole). The brackets have a stop – they come in a few versions that allow for less or more cantilever. I opted to have the spools mostly resting on top of the rack, but that's up to you. It will depend on how sturdy your shelves are and how much clearance you have in front (i have a heating pipe in front, so wanted the holder more towards the back).

The rollers are optional, and can be used in conjunction with the filament guides for the PTFE tubes. They roll well enough that I can have the spools on the rack, feed them through my buffer, into the MMU, and into the printer, without issues.

The guides simply snap on in any location where you need them. As you can see, in my setup the PTFE tubes are fed into the guides, where they take the filament from the spools that are sitting on top of the rack.