[DIY] Parametric Spool Adapters for Bambu AMS

I had to design spool rim adapters for CCTree cardboard spools and for YXPolyer plastic spools, despite them claiming compatibility with Bambu Lab's AMS multi-filament changer.

These spools would not properly rotate backward as, when new, they are so full that the filament stack rubs against the feeder, preventing the spool's rims from firmly sitting on the rotating axles.

So I whipped up the parametric model below that, theoretically, can be modified for other spool brands.

All the Fusion 360 CAD, STEP and M3F files are on Github

Am too lazy to upload to Thingiverse / Printables / MakerWorld... Feel free to do so, including copying, remixing, expanding, whatever.

Happy printing to all !

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Design

Inspired from DesignCraft's CCTree cardboard spool adapter ring

But at first it wouldn't fit at all on my CCTree spool, was too small by at least 1mm in diameter. So I scaled it up to friction fit but, even though, it was never entirely flat against the spool and didn't feel like it could be trusted for hours of AMS filament swaps.

So I designed a version with a rim lip and 6 little tabs that positively latch onto the cardboard rim:

What a change, the ring now felt very secure and the spool was freely rotating in the AMS.

So, simply copied that model and changed the parameters for YXPolyer. The lip and tabs also work with that spool's rigid plastic material.

Design parameters:

1st section: describes the spool size needed to be compatible with the AMS. Should be left alone.

2nd section: describes the non-spool dependent parameters, i.e. the shape of the tabs (clip_), of the outside flange, etc. Offset_inside_ring is the play to leave between the spool's outside radius and the inside radius of the ring. Allows for a loose fit and inconsistencies between spool diameters from a supplier, as the lip and the tabs are the ones securely holding the ring.

3rd and 4th sections: parameters for each spool brand. For a new spool type, either tweak the CCTree parameters and rename that Component or Copy / Paste New the CCTree Component. Then follow these steps:

measure the spool width and update cctree_spool_width (preferably measured through the spool's center, not from rim edge to edge as they can be warped)
measure the spool diameter → cctree_spool_exterior_diam
measure the thickness of the spool walls → cctree_spool_wall_thickness
open the 1st sketch in your Component and change the text:
adjust the text size if necessary → cctree_text_height
adjust the flange size to not obstruct the openings for the filament end → flange_overlap
and that should do it. If the timeline didn't light up like a Christmas tree with warnings and errors, felicitations ! If not, good luck 😅
check the thickness of the resulting outside flange: it should be at least 2 printing-layers thick, i.e. 0.4mm. Otherwise it'll be too thin and break when pulled from the bed or when installed on the spool. If too thin, measure again your spool width and see if that can be decreased by fractions of a millimeter. If not, try to bump up bambu_max_spool_width, though at your own risk...
after printing a sample, if the tabs are not grabbing the spool enough, or if they make the installation of the ring too difficult, adjust cctree_clip_overlap