Designing this took weeks of work and testing.   Your boosts are an appreciated form of thanks 

Update: I added a mirrored version of the bases and the manifold for those that want to mounth this somewhere other than on the printer or for those with a k1 max.

Update #2: Enclosure file is up! check it out over at. https://makerworld.com/en/models/105490#profileId-112584

Update 3: changed print profile to use glued dowels to hold the two parts together.  I think this will sove the most common problem of getting things to line up.  

This solved my biggest beef with day to day use of the printer……. changing filaments. 

I had a few goals.

1. Be able to load filaments from the front.
2. Be able to leave my regularly used filaments in place
3. Have a place to hold filament when not in use to keep it from unrolling (you cant see it but there is holder behind each loading spot on the manifold.
4. be quiet - ie no rubbing.

You're gonna need a few parts

• I used 4mm OD, 3mm ID PTFE tube to try to reduce friction. I ordered this stuff. https://amzn.to/46UgvDl (bambu labs 4mm/2.5mm should work but you will definitely need to bevel entry points.)
• PTFE tube connector. I used the Bambu labs one https://us.store.bambulab.com/products/ptfe-tube-connector you could also use one of these from amazon https://amzn.to/3RLyR5f . alternatively you could use a single piece of tubing that runs all the way from the extruder to the manifold but I wanted the option to disconnect at the machine.
• 8mm x300mm rod. https://amzn.to/3RAq5qj alternative link: https://amzn.to/47hFPmF
• M10 push connector for PTFE tubing. I used these https://amzn.to/3TcCwKm
• M3 Heat set threaded inserts. I used ones from this kit. https://amzn.to/4a8hv9L but you could just buy M3 size which is the size I use the most for projects like these. https://amzn.to/3NksT8C
• Sixteen 608-zz bearings. I use these. https://amzn.to/4afBenR
• M3 screws. I think I used mostly 10mm, but if you dont have a huge assortment of these already you should so get a variety and figure it out!
• nylon washers I used ones from this kit. https://amzn.to/41hQDQz 1.5mm thick. but I will also include an .stl file. you should be able to print them.
• I used non slip glass top pads that I had around the house to keep it from sliding around. I am sure many different things could be used. These are what I use and it wont slide at all. https://amzn.to/3Njf5uU

How to do it…. you have to be detail oriented and if you skip any steps or have any rubbing it will cause problems.

1. Print bodies as indicated in file notes.
2. While they are printing soak the bearings in denatured alcohol overnight, dry them out and the relube with a light oil like 3 in 1 oil or I used sewing machine oil. you need the bearing to spin like you would want them for a fidget spinner.
3. Heat sink the threaded inserts into the holes on the front of the bases.
4. using CA glue connect the bases together using the dowels.
5. Screw the manifold to the front
6. Fit TPU bearing covers over the bearings.
7. The fun part…… slowly fish the rods from right to left inserting washers and bearings as you go. there should be a washer on each side. this keeps bearings and rolls from rubbing the sides. The left side of each roller space should have the beveled bearing covers with the sharp edge to the left. in cross section it should look like this. The orientation of bearings on the right doesnt matter. Once they are all in make sure the TPU covers area aligned and not rubbing. they should spin freely. 
   
    
8. once you have all 8 pieces through put screw the cover on to hold the rod in place - if you are printing the enclosure you can just leave them off the enclosure will keep the rods from coming out. 
9. Assemble the manifold.
   1. cut 4 pieces of PTFE tube perfectly square and long enough to leave about 2-3 cm sticking out from the top of each loading point. seat them all the way.
   2. screw the PTFE M10 connector into the manifold. 
      
10. Place a coupler on the end of the PTFE tube coming out of the machine and attach PTFE tubing from that point, through the holders to the manifold. 
    
    
11. PRINT AWAY
     

EDIT:

DrHO1337 over at printables has some code on his model (found here https://www.printables.com/model/621741-bambu-lab-manual-material-system ) that might make material changes easier for people who want to do simple prints with multiple colors. This model was initially just made for use with single color prints. give it a try. I havent used it. and give the guy a thumbs up over there.

here are his instructions:

In order to use the slicer correctly, like an AMS, you have to change the filamentchange gcode in the printer settings.
The corresponding g-code is in "noAMS.txt".