MP3DP v4 mod, Aza's 3D Chameleon MK3/MK4 MMU

Ordered 3D Chameleon kit (MK3?) couple months ago. Didn’t assemble partly because I wanted to await RMRRF updates/announcements.

Have clearer understanding now, so here we go…


  • Below is the MK3 kit I ordered 2/5/2024. Contents of the current MK4 kits probably differs, but is nice to see Bill’s kit has many/all printed parts included, and preassembled…
    • Includes two steppers, the “Selector” (CAM moves sliding parts that engage/disengage bearing wheels to engage selected filament ) and the “Extruder”.

Pic above doesn’t show all the greatly appreciated bubble-wrap/packaging that ensured safe shipping.

MK4 Overview / News

  • 2024/4/20 ~4min chat with West 3D at RMRRF

    • Overview of MK4 and open source Accessory updates (~$30 to source parts).
      • Filament Cutter, 20KG servo
        • Q: How to reduce weight Light
      • Motor encode attaches to extruder motor, auto calibrate without needing to explicitly configure distance.
      • OLED display (1366??? or 1306) for status
      • Runout sensing, enables endless spool. e.g. Switch to next/random filament.
      • Filament drybox with buffer (kind of…).
  • 2024/4/20 Chat with Mandic at RMRRF

    • Similar questions and info to West 3D.
  • 2024/1/18 MK4 overview at SMRRF by Nero3D

    • MK4 Uses TMC stepper drivers, sensorless homing, detect hitting extruder, enables more automation/troubleshooting behavior.

Resources / Related

Alternatives considered




Will be good to see this go together and see the differences between it and the ercf. Good luck with the build!

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So looking at the open box photo, it is using 2 motors for 4 colors. I don’t recall seeing how the extruder transmission switches colors with the second stepper and I’m curious how that works. Can you describe it?

Yeah, one of the steppers has an offset cam that moves a sliding plate that pushes/pulls bearing wheels to engage the desired filament against an extruder gear on the 2nd stepper. The other stepper extrudes/retracts whatever’s currently engaged. Not sure if/how this’ll work with TPU/flexibles, we’ll see…

Best explanation I’ve stumbled onto so far is Chris Riley’s. Chris walks through assembly of the cam/gear, but my kit came assembled already. I just have to hook up, configure macros and tune I guess. Am following his recent series…

Curious if anyone’s found guides that worked out easier for them to get up an running?

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I watched the Videos that Chris’s Basement put out and those seemed to be pretty well done. Is there something that you feel is missing from it??

I liked his Chameleon series. I’ll be rewatching since it’s been a while. Doubt much is missing other than things specifically needed to mount to my MP3DP v4. Will make notes and share info as I make progress…

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This multiplexing feeding extruder gear just feeds to your direct drive extruder by pushing filament through the y tubes and into the reverse Bowden tube connected to the direct drive extruder on the hot end. It doesn’t serve as a Bowden extruder, so I would think it should work just fine for soft filament.

Does it actively feed during printing or just during the initial swap and purge?

Assembly, Mount 3D Chameleon Switch near Y Max

Created mount to attach 3D Chameleon Switch to V1E MP3DP v4. 3D Chameleon instructions has links to various mounts for various printers, but I couldn’t find one for my printer :
“Check Thingiverse: or Printables: Printables

Shared/latest at Will share on printables when done.

Klipper users can optionally avoid needing the switch, and instead use macros, this involves wiring up (e.g. endstop GPIO + common ground) from the Controller board to the 3DC mcu. This approach will help speed up filament changes after the next 3DC firmware is released. All that said… Wiring up the switch is how most people seem to be setting up, plus having the physical switch makes diagnosing/troublshooting easier. My plan is to reduce variables, get slither of end to end functionality working, then optimize from there. Assuming some other shiney project hasn’t taken priority by then.


  • 2x M3 x 10mm button head bolt
  • 2x M3 Hex nuts
  • 2x M3 T-Slot nuts
  • 1x M3 roll-in half moon T-Slot nut
  • 1x M3 x 8mm button head bolt
  • Skinny hex/philips drivers

Assemble by threading belt through the printed part’s open slot. Fasten bolts in numbered sequence. 3DC switch has thru hole components, so use the hex nuts as a spacer between the 3DC PCB and printed mount. After snugging up bolts, verify microswitch triggers within 1-2mm Y Max. If extra arm reach is needed, then, carefully bend microswitch arm so arm lands on right gantry truck.

Check your wiring/umbilical expected range of motion is unaffected and nothing gets snagged/blocked. Personally Needed to ziptie and tidy up the loose wiring for my X endstop to avoid snag on the 3DC switch mount.


Short update… No multi material print yet. Experienced some teething issues during first/early attempts to filament home and load. Tried and trying various things, thanks to suggestions from various 3DC community folks… e.g.

Nice that the kit was pre-assembled, no need to print anything except for the 3DC Switch mount. Nice that there’s not too many parts. However, although filament cutter 3D Clippy is ‘optional’, it seems like a very useful should-have, or must-have feature even. Still digging through the 3DC forum…


You have it running yet @azab2c ? at the rate its taking me to get all these parts printed for the ERCF it might be another month before I see a multi color part LOL

Nope. Switched to some other project(s) for a bit…

Partly because am waiting for Bill to post details/designs for the updated 3D Clippy and associated firmware. Thinking filament clipper will help reliability. Am refreshing more than a reasonable person should.

Also, I need to fix how filament feeds through the 3mm ID 4mm OD PTFE tube, to the PTFE pneumatic fitting, to the BIQU V2 H2S Revo. During filament load (unrelated to MMU or 3D Chameleon), am often seeing curled filament find a way to get wedged/stuck.

Have been using 3mm ID instead of 2mm ID to reduce filament resistance (seems like something some Voron folks do). However, although filament slides through PTFE very easily, the end of that wider 3mm ID results in filament hitting a ledge/restriction in the PTFE fitting. Ideally the PTFE fitting’s ID would be tapered. Am looking at alternative PTFE fittings and/or use drill press to taper fitting’s internals and/or switch to 2mm ID PTFE and/or something else(s)?

Even if I change/mod the PTFE fitting, am finding that the filament switch lever often needs flipping during loading. This also seems related to openings/internals not chamfered/tapered. So, am wondering whether the Chameleon’s extruder can ram past these obstructions, we’ll see…

Did you happen to talk to this fellow at RMRRF?

He was walking around showing his unique solution for bowden tube connections.

I didn’t quite grok the need/use case he was describing- but his fittings were very interesting.
Edit: his description of the use case sounds exactly like what you’re trying to solve.

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I only noticed him sneakily trying to get free promotion by hanging these signs up everywhere. Seemed shady to me.

Hmmm. That thought didn’t occur to me…
It’s certainly not like the low dollar tables were expensive.

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I see what he’s going for here … Basically, he’s taking a compression fitting, like what’s used in water hoses in your home (how a pipe is cut and a shutoff valve is inserted, for example)


and modifying it to fit PTFE tubes and screw into your extruder/hot end in place of the rather finicky PTFE connector, although it seems the middle piece screws onto the tube (as evidenced by the marks on the tube below but not above the middle piece) instead of sliding on and being “crushed” by the top nut to grab the tube. I’m not entirely sure it would help the issue at hand… the tube would still have to go all the way through the fitting that’s screwed into the hot end (it’s not connecting two different pieces of tube, it’s one piece all the way through), which would be equally as possible to do with a standard claw-style fitting (if it’s the right size, anyway). You would just never have to worry about it pulling itself back out ever again, like you might with the claw-style fitting.

Because I’m new, I was only allowed to add one picture (understandable, they don’t want people spamming the forums). So here’s the second picture I wanted to add, the part about the ferrule being “crushed”:

My novice complaint is that I don’t have trouble with the existing fittings.

I can imagine getting rather pissed off every time I have to find a wrench to take off the ptfe tube lol

If only you had access to a machine that could print a quick-access wrench with a thumbwheel that you could keep by the machine… :thinking: :smile:

True, but I just don’t want to deal with it lol