Prusa i3 Mk2s MMU Frame Spool Support (4 Spools) Space Saver

thingiverse

Space is a premium for me, so I created a 4-spool holder that attaches to the top of the frame, making it easier to feed filament into the extruder without struggling with bottom-fed extruders. I've been testing this setup for months, refining my design until I'm satisfied with the results. Printing at speeds up to 70mm/s shows no noticeable vibrations or rocking, and print quality remains unaffected. Some clone printers may experience frame bending due to added weight, affecting print quality, but with the Original Prusa i3 MK2s' metal frame, I haven't encountered this issue. I normally print PETG at 20-40mm/s with rock-solid results. The spool holders can accommodate spools up to 100mm wide between supports, and staggering over supports allows for wider spools. However, most of my spools are under 100mm wide. The PTFE tube bend is higher than the highest point the nozzle can reach, ensuring it won't interfere with tall prints. Parts List: - 2 Prusa i3 Mk2s MMU Modified Extruder For Bowden Style Input - 3 Spool Frame Supports - 4 Filament Guides - 16 Bearing housings - 4 end Caps - 4 250mm long 4mm OD 2mm id PTFE tube - 4 M5 x 7mm brass inserts - 4 Festo QSM-M5-4 Push-in Fittings - 16 Bearings from the Prusa MMU Filament Rollers - 2 500mm long 8mm OD 6mm id Carbon Fibre rods - 3 160 x 2.6mm Zip Ties (same ones supplied by Prusa) I used M5 x 7mm brass inserts found on Ebay at a reasonable price, as they matched what Prusa used but were expensive. Festo QSM-M5-4 Push Fittings from RS Online are the same as those included with the MMU. https://uk.rs-online.com/web/p/pneumatic-straight-threaded-to-tube-adaptors/1216037/ The Bearing housing/Wheel design was modified from https://www.thingiverse.com/thing:1832235, with slightly higher sides. I modified the Prusa Extruder to accommodate a 4mm OD PTFE Tube from the Filament Guide. https://www.thingiverse.com/thing:2822229 The Bearings are from the MMU Spool holders, saving me from buying new ones. The Rods are 500mm long 8mm OD 6mm ID Carbon Fibre rods, purchased for their unique properties. The inside Diameter of the Bearings is 8mm, making them a tight fit for the 8mm rod, which I sanded to make slightly thinner and reduce friction. The Holes for the brass inserts are 7.2mm diameter, allowing for material expansion and a press-fit assembly. The Filament Guides have a slight flex, allowing them to snap over the rods and slide freely into position. The Supports have an internal channel for zip ties, which is essential as they help distribute the weight of the filament and prevent vibrations or rocking. The end caps prevent bearings from falling off and highlight the ends of the rods, making them more visible. When cutting PTFE tubes, use a sharp craft knife instead of side cutters to avoid crushing and ovalizing the tube.