MMU3 UltiMulti Printable Parts

Ultimulti MMU3 project is a DIY multi-material solution developped in parallel with the Original Prusa MMU3, with the ease of use and reliability being the two key improvement objectives, while still maintaining a reasonable reverse-compatibility with the earlier MMU2S. Ultimulti provides more visibility and access to the filament path as well as other hardware components. This comes in handy in the moment you need to clear out a filament jam or resolve a similar problem at runtime.

• Prusa MMU2S to MMU3 Ultimulti upgrade: with just an addition of a few hardware components and printing new plastic parts, you can build the Ultimulti.
• For Ultimulti MMU3 build from scratch; use the Prusa MMU3 hardware components and just print the new plastic parts to get Ultimulti.

The most notable advantage of this system is the easy idler lock which enables you to open and close the idler-body with just a one-handed flick. No longer you have to undo two bolts to reach the MMU's internals - and then re-set the idler tension on both sides. Single idler tension spring inside the lock also mean an easy and precise tension calibration. It allows the MMU unit to home idler axis more reliably due to the single spring having a longer effective deflection range too.

Ultimulti should ideally be used as a full set of plastic parts of the most up-to-date revision. In case you opt to use just a part of the Ultimulti plastics on your MMU, please refer to the reverse-compatibility notes on Github and part descriptions in the link below.

When printing the plastic parts, the 0.15mm layer height is advised. PETG material is tested to work reliably. As with the MMU2S, the plastic parts are very sensitive to print defects; especially the first layer adhesion and part warping /lifting up from the heatbed. Verify the filament used is dry, the first layer is laid correctly, the part cooling percentage high enough to maintain the dimensional accuracy and the nozzle temperature high enough to ensure a proper layer-to-layer bonding as well as print surface adhesion.

The MK3S+ Precise Calibration Chimney should be used on the MK3S+ extruder. Note, there were several versions of the MK3S/+ MMU Extruder Idler parts. Use the latest one.

The assembly is similar to the Original MMU3. 
@KM323_1097999 made an excellent assembly instructions writeup in the comments section. 

 

Hardware required:

To upgrade MMU2S to MMU3 Ultimulti, getting a Prusa MMU3 upgrade kit is higly advised as it will get you all the necessary new components.
Apart from the MMU2S parts, you will need:

• MMU2S data cable can be modified to provide a more refined 5V voltage level to the electronics board's logic (as is explained in this video by Chris Riley). A stable 5V supply is crucial! Ideally, the MMU3 cable and PD-board addon are the best option available.
• 2.5mm ID PTFE tubes should be used. (as on MMU3) 5x650mm, 5x19mm, 1x360mm
• 19mm and 360mm PTFE tubes can be clear color for better filament visibility, however the rest should be regular non-clear PTFE tubes (for reduced friction)
• the rear of the unit is designed to be equipped with 5 E3D collets to retain the PTFE tubes in. (as on MMU3). Alternatively, you can use 5x M6 or M10 pneumatic fittings.
• Selector utilises the MK3S fs-lever style 10x6x2 magnet and a 7mm magnetic steel ball (as on MMU3). Note, the MK3S and MMU2S balls are not magnetic!!!
• Idler is meant to be attached to the motor shaft using either a flat-faced metal coupler (MMU3) or a printed adapter with a modified GT2-16 pulley. Remember, idler concentricity is crucial! Original Prusa coupler is of better quality than the chinese ones.
• M3 washer for the Chimney calibration screw. (MMU3)
• then just sum bolts n nuts. The majority can be harvested from MMU2S such as M3x10, M3x18, M3x30. Extra M3nS square nuts are required.
• optionally, 8x6mm magnets for motor visualizers
  
  The magnet, washer, blades and fasteners can be sourced from MK3S and MMU2S spare parts bag.
  
  
  Printable parts for various other modifications of UltiMulti such as:
  - partial MMU2S upgrades or more reverse-compatible parts
  - double Idler lock version
  - top-mounted electronics version
  - self-standing MMU unit integrated onto the cassette buffer 
  are available at: https://github.com/davidkerny/BUZA-ULTIMULTI