"Fixing" the MMU3 for CORE one - COREBOXX premium

The Official Prusa MMU3 is proven to be the most reliable multi-material solution on the current market. However, it comes with 1 big flaw for user experience; the complex buffer solution requires almost a full desk to function, clutters the workspace, and is hard to load. 

Let's take a look at how I fixed this, with COREBOXX premium;

COREBOXX is an all-in-one platform for neatly storing, organizing, and managing your MMU3 and filament. It can be assembled with little parts, like polycarbonate panels, some hardware, and 3D printed parts for the frame, handles, and accessories. These all can be printed right on the CORE one itself, and make for a fun project to build and assemble.

The design is made to integrate fully with the design language and appearance of the Prusa CORE one itself, while retaining all the functionality of the printer, including the top ventilation grille. 

Version explanation;

To tailor to both the non-MMU and MMU users, I have made 2 versions available;

Premium version (paid model);

• Magnetic mounting to the CORE one frame
• Full support for in-built MMU3 with built-in passive buffer system
• A service hatch to easily maintain the MMU when necessary, without removing a bolt.
• Extra mounting points for future accessories
• Short MMU to the nextruder bowden tube of 52,5cm
• Passive, rewinding spoolholders for neat MMU buffering
• STEP files for easy modding
• Pre-sliced gcodes
• Fully prepared Prusaslicer project files

Standard version (free);

• Mounts on top of the CORE one machine, or sits beside the machine on the desk
• Supports  5 spools of 1kg filament (up to 72mm in width)
• Keeps all functionality of CORE one (including front access to chamber vents)
• Is fully 3D printable on the CORE one itself.
• Is designed to feel and look in line with the design language of CORE ONE.
• Has a full-access door that closes magnetically
• Has a strong frame design, which mounts with sturdy heat-set inserts

Space savings;

As mentioned in the intro, the main issue I wanted to solve for myself was the desk space needed for the normal MMU3. The standard setup requires the printer to sit on your desk, with the MMU mounted on top. Then, you will need space on the side to mount the buffer, as well as a large section to place your 5 spools of filament. All of these stations are connected via a total of 6.5 meters of PTFE tubing! Loading is also cumbersome, where you need to guide each filament through 1.3 meters of tubing and load it through each buffer manually. 

COREBOXX has a different approach. It remounts the MMU upside down in the back of the system, opening up space in the front. This is where all 5 spools sit side-by-side, right at the front, and all accessible at the same time. They mount on a so-called “rewinding” mechanism, which is based on the Filamentalist for Klipper/ERCF. This mechanism actively turns the spool backwards when the MMU feeds the material back, effectively rewinding it back on the spool directly! This eliminates the need for a buffer and allows for a direct path between the spoolholder and the MMU. To load the system, you just need to feed the filament 65cm from the front of the MMU3. Loading all 5 spools can be done in under 1 minute!

The ecosystem;

COREBOXX goes further than "just organising your deskspace. It is made to improve the user experience in many more ways. To show you what I mean, let's talk about the ecosystem.

Placing the filaments inside an enclosed chamber comes with the benefit of being able to control the environment of the filament. This means we can actively heat and recirculate the air to draw the moisture out of your filament. I wanted to add this to COREBOXX in a Smart way. Therefore, with the help of 2 good friends, I taught myself how to design electronics. In the end, the project ended up bigger than Coreboxx itself, but I came up with:

Semi-smart;

Semi-Smart is a set of PCBs that combine a programmable Arduino with the Prusa GPIO hackerboard neatly into 1 board. This combination allows you to get smart, flexible, and programmable control through the Arduino while also being able to communicate to and from the printer via the hackerboard! This means we can do a few things;

• ✅ We can safely heat the chamber with a 200W PTC heater and targeted temperature and humidity control (max 45°C)
• ✅ We can visualize the process with an OLED Display that shows current/set temperature, humidity, and custom messages like layer numbers
• ✅ We can easily set and edit the heating parameters via the simple, 3-button user interface
• ✅ We can turn the heating automatically on or off based on the state of your printer. For example, turn it on while printing, and off when in standby. 

Summarised, Semi-Smart allows you to add a heating function to your COREBOXX, with smart software co-developed with @3DMonkey. A more detailed explanation of Smi-Smart can be found here.

But I did not stop there.  Once we have drawn the moisture out of the filament, we still need to remove it from the air and store it somewhere else to prevent it from re-entering. This can be done with;

Silica gel container

I have also made a simple add-on that can hold a large amount of silica gel. It consists of a very ventilated container with a screw-on lid. It can be easily added, and the add-on is available for free via this link.

Of course, we still need to look good when doing all this. which brings me to;

RGB LED strip lighting

The Semi-Smart PCB also has a connector for a ready-made LED strip, which lights the inside of COREBOXX in every color imaginable. This can be used for fun, when set to a fixed color to suit your printing space, desk, or room, or to indicate the status of the printer, meaning it will turn green when printing, and blue when in standby! 

More information can be found here

Other Add-ons, and future ideas;

I will not stop here, and many more add-ons are on their way, or have already been made by the community! For example, you can;

• Use the UltiMulti inside via the UltiMulti legs
• Use the gravity-based Rewindr of @LudvigBroome
• Add per-spool LED lighting from @Krosta
• Or improve your experience with many other improvements users have made

Some other things I am working on myself are;

• Automated grille operation of CORE one. 
• Active drying by periodically removing the saturated air and replacing it with fresh air
• Bluetooth connectivity
• And much more

Get COREBOXX for yourself

With all the add-ons, it can be a bit unclear what to purchase if you want to build your own COREBOXX premium.

You'll need to make 2 purchases to build COREBOXX premium (Outside of the MMU3 itself)

• You can buy the project files directly through my listing to gain access to all 3D printable parts
• All Panels, hardware, bearings, etc, can be purchased worldwide via the Hardware kit from Blurolls

Then you can add options as you like.

• Semi-smart can be purchased as a ready-made kit to add the heating, as explained above
• An RGB LED kit can be purchased in addition to the Semi-Smart to add the internal lighting.

As for the MMU3, you can use the MK4S kit version, which is the cheapest route to go. CORE one lite can also be used, but this will be more expensive, and only add parts we don't need for COREBOXX

Links;

YouTube video on COREBOXX;

COREBOXX listing;  PRUSA CORE one - COREBOXX premium 
COREBOXX premium kit: Blurolls Prusa Core One Filament Box
Semi-Smart kit; Prusa Core One Coreboxx Electronics 
Semi-Smart LED add-on; RGB LED Strip for Prusa Core One Coreboxx 
UltiMulti add-on; UltiMulti for COREBOXX
Rewindr from Ludwig; [A5] Rewindr -  by Ludvig Broomé
Per-Spool LED lighting; COREBOXX & SEMI-Smart addon - by Krosta 
Complete add-on collection; COREBOXX ecosystem Collection