Ok so, let's finish this off (maybe).
As you can see by the cover photo, a brilliant mind, Xoffroad, designed a replica of the AMS Lite unit and it fit the bill perfectly. My original design, was a couple of double spool holders mounted at the back of my bench. This didn't really work out too well as the filament was coming into the unit at a bit of a sharp angle.
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Back to the drawing board, but someone else had done that, so why not. If anyone would be interested in me publishing the prints for the double spool holders, let me know.
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Anyway, I've been using the AMS Lite dupe stand for a while, but had an issue with the spools falling off, Bambu Lab spools funnily enough, and needed another solution. At time of writing I'm using the the Ikea 365+ 10.6L dry box hack by NeosSTX and the filament feeders are by SpectreGadget, I've also changed to having the unit mounted side on.
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This method works, but I'm still not happy with the setup, so it will undoubtedly change in the future.
So, back to the BMCU itself. The short story is, it works and does a great job at doing what it's supposed to do, which is change filament and feed it through to the hotend. There is a but though, I'll get to that!
Stepping through the testing and final print process, I will give you a visual of how it went for me. First, was addressing the filament spool mounting problem as described above. Then feeding the filament into the unit which I described in the previous article. I first checked that the unit had been detected and all spools where shown, they where, then edit the AMS screen with the actual filament I had loaded.
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Next step was to print the requisite test piece using these colours, for some unknown reason I didn't take pictures of the print #facepalm, but it was just a grey triangle with the letters A M S in the blue, green and orange as loaded up above. Pretty uninteresting anyway. Then it was on to printing the thing I had promised my daughter ever since getting a 3D printer. So I loaded up the requisite colours and hit go, and honestly I think it turned out great.
 Why did I print this you may ask? Well as my username suggests I also build electric guitars and basses, and this project is to replicate the Squier Hello Kitty model guitar shown below.  |
I have done a few more multi-colour prints since then, and I have them documented below, as well as a time-lapse of one of them.
So everything was fine and dandy and everything was great, well almost, now to the but!
A major issue I was having is, losing connectivity with the printer. Now, I thought maybe I had a dry solder or something like that, and decided to do a bit of Reddit and Google digging to see if anyone else has had the same problem. It turns out quite a few people did, and there has so far been no answer as to why it happens. Frustratingly, it is more of an annoyance than a problem. Once a print has started it will continue on as if nothing is wrong, but an error will display on the screen, as well as in the slicer. The “fix” for me at the moment is, let the print finish successfully, which it does, then turn the printer off and back on, and everything is back to normal.
This issue seems to not only happen with the kit, but also with the fully assembled unit that you can buy. It also doesn't happen for everyone. Maybe I was unlucky, maybe a firmware update will address the issue? From what I have been able to find out, the designers have not responded to anyone raising this problem as of Sep 2025.
Problems aside, it does work and doesn't affect print quality at all. I've popped a couple of photos of some of the prints I've done below, while testing it out. The Flexi-Octopus does have an issue with the eyes, but that was user error and nothing to do with the BMCU.
…and here is a link to the timelapse of the Flexi-Octopus being printed
The main reason I got this unit, apart from the cheapskate in me, was to use it as an Auto-Refill for changing out same colour spools on long print jobs, and going forward that will be it's main use.
So, would I recommend getting this unit, yes, will you have the same problem I had, maybe, but that problem aside, it does work, and it is a cheap and fun way to turn your A1 or A1 mini into a multi-colour printer.
Happy printing!
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