MMU2/MMU3 Buffer w/ Magnetic Manifold Mount

8/8/24 - updated magnetic_mmu_buffer_top with proper tapered PC4M10 threads. The item I remixed has incorrect threads for this connector. My thread design can be hand-turned in.

This is a remix of Manzn's MMU2s buffer to have a magnetically mounted top/manifold and no wrap around the wheel for a very low friction path through the buffer. In fact, I found that my filament was preferring to flow out towards the spool vs fill up the buffer so I had to introduce a small bit of friction between the filament spools and the buffer assembly. The amount introduced by this piece is negligible but it stopped the filament from pushing back out towards the spool and now fills up the buffer properly. Usually friction is a problem but not here. 

Mounting tabs are generic. If you want to build mounts, the footprint of the mount tab holes are as follows:

4mm holes
250mm high x 85mm wide - center to center measurements

Print all pieces and additionally you need wheels. I used these wheels as they don't have a drastic overhang that may result in rough printed results: https://www.printables.com/model/313118-improved-spool-wheel-print-without-support-for-rmu

All pieces print without supports.

Files are larger in size as I export these from Fusion360 with the highest resolution possible for the cleanest curves in the print.

This uses the following hardware:
(2) M3x10 socket head screw
(2-8) 10mm x 2.6 rare earth magnets - two sets keep my lid put nicely in the vertical orientation
(5) 608 bearings (skate/rollerblade common bearings - use the cheap ones)
(10) PC4 M10 connectors

Easy printed axle is kept in place by end blocks.

Middle and bottom glue together with CA (superglue).

Magnets glue into place with a drop of CA glue.

I removed the grease from the bearings so they turn easier and left the covers off.

Lid also uses PTFE inserts to help keep the path aligned and to minimize friction. There is a tube cutting jig(see pics). One is to angle cut the filament and then the straight one is to cut the resulting angled end off to length. I used 4OD, 3ID PTFE for this part.

Remixed to have a magnetically mounted top.