Multi-material Kit MMU3 for Prusa MMU2S, MK3S+ and MK4

Prusa is a Czech company dedicated to the manufacture of 3D printers and other 3D printing products, as well as creators of their own software and hardware. Founded in 2012 by Josef Prusa, it is one of the most relevant companies in the 3D printing sector, shipping thousands of printers every month all over the world.

The Multi Material Upgrade 3 (MMU3) is the third generation of the Multi Material Upgrade add-on, which enables the Original Prusa i3 MK3S+ and MK4 3D printers to print with up to 5 filaments at the same time. It is also possible to upgrade the MMU2S kit to MMU3. The MMU3 upgrade has:

• A completely updated firmware.
• Redesigned plastic parts and added metal parts.
• Improved electronics.
• Updated filament buffer.
• Bidirectional communication with the 3D printer for status upgrades (error codes displayed on the printer's UI).
• Automatic repetition of actions to avoid unnecessary "user attention" errors.

It is IMPORTANT to keep in mind that the kit does not include 3D printed parts or tools.

The Prusa i3 MK3S+ is an open source fused filament deposition (FDM or FFF) 3D printer created and designed by Prusa3D. It is the latest version of this family of renowned printers and is also one of the most widely used 3D printers in the world. Perfect both for users who are just starting out in the world of 3D printing (due to its ease of use and low cost) and for professionals (due to its great potential and results), it is excellent as a main printer; but as an auxiliary printer it is very powerful when it comes to, for example, creating a 3D printer farm.

Image 1: Part 3D printed with the MMU3 kit. Source: Prusa3D.

The Prusa MK4 is an open source and open material FFF 3D printer created and designed by Prusa3D, distinguished by its modernized sturdy chassis, high speed printing capabilities, ease of maintenance and use, a wide range of safety functions and compatible materials, new 32-bit connected architecture, and the upgraded extruder Nextruder. 

MMU3 uses a direct drive feed and a single PTFE tube to automatically feed the selected filament to the extruder and also automatically change materials when it's time. The motorised selector head has a F.I.N.D.A. filament sensor and a built-in blade, which prevents filament jamming.

Image 2: Part 3D printed with the MMU3 kit. Source: Prusa3D.

With the MMU3 it is possible to detect not only that filament is present, but that it actually reaches the Bondtech gears. The filament sensor detects when the tensioner gates open a little when the filament separates the Bondtech gears. The MMU3 add-on is much more reliable when reloading filament and the calibration process is also simplified.

The MMU3 also comes with the filament buffer, a device designed to prevent filament tangling during the loading/unloading process. The buffer allows the five filament spools to be positioned more freely and also saves space in the work area.

Image 3: Part 3D printed with the MMU3 kit. Source: Prusa3D.

The MMU3 is a unique multi-material printing add-on that is fully integrated with the printer, so everything is perfectly synchronised and works seamlessly as a single unit.

In addition to the usual materials such as ABS, PETG or PLA, the MMU3 also works very well with soluble support materials (BVOH or PVA). This offers the user the possibility to 3D print highly complex parts using one or more build materials in combination with soluble support filament.

Image 4: Part 3D printed with the MMU3 kit. Source: Prusa3D.

The Slic3r PE laminating software comes with full MMU3 support and a set of useful features such as "smart cleaning tower", "cleaning in fill" or "cleaning on object". These features will help to save time and filament as well as maintain a perfect transition between colours/materials. The cleaning tower, for example, is a compact, partially hollow block next to the printed object, where the "old" filament is purged and the pressure in the nozzle is stabilised. With "cleaning in fill", the infill of the printed object is used as the cleaning tower, and with "cleaning on object" another object is used as the cleaning tower (that can be used for functional purposes).

Image 5: Part 3D printed with the MMU3 kit. Source: Prusa3D.

Printing with the MMU3 is similar to printing with a standard Prusa I3 MK3S+ or MK4: Laminate the model, export the Gcode, transfer it to an SD card and start printing immediately without any problems. With the new sturdier design, updated software and hardware, and expanded compatibility, the MMU3 kit is more reliable than ever.