Improved MMU2 Buffer for Prusa Enclosure V2

thingiverse

The first version of this MMU2 buffer (https://www.thingiverse.com/thing:4138220) was a significant improvement over Prusa's stock model, loading/unloading and printing are much smoother now. I completed a 5-day print with 2400 layers and 2200 filament changes without any MMU failures. However, I did experience some under-extruded layers and narrowed down the root causes to the following fixes: 1) The 2.5mm Plexiglas on the outer sides can flex too much. The stiff filament can squeeze out and cause problems. Solution: add thick printed top and bottom plates with profiles to hold all Plexiglas dividers in place. 2) There is still some unnecessary friction in the system, and the filament rubs against the metal end of the PC4 M6 fittings. Solution: switch to PC4 M10 fittings where the PTFE tube goes through so no metal touches the filament. Bill of Materials: Plexiglas https://www.tapplastics.com/ 6 x Extruded Acrylic Clear 2.5 mm Thick, 125 mm Wide, 350 mm Long Fittings 10X Fitting PC4-M10 https://www.amazon.com/gp/product/B07V3G71HK/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1 Bearings https://www.vxb.com/ 5X 10 X 19 X 5 bearing Screw, Nuts 15X Hex Nut M3 10X Sq Nut M3 25X SHCS M3 X 8 4X FHCS M3 X 10 4X BHCS M3 X 8 7x SHCS M3 x 6 PTFE Tube https://fluorostore.com/ I'm using 3/32" ID X 5/32" OD with good results so far. So far, I've printed a 30-hour Santa, 1010 layers and around 900 filament changes. Perfect print, no MMU or extrusion errors with the new buffer. A 5-day Nefertiti job, with 2400 layers and 2200 filament changes is ongoing. As always, STEP file included if you want to modify it.