When filament runs low, the original Bambu spool still takes up as much storage space as a full one.

I designed this Modular Resizable Spool to solve that problem.

The central hub locks together like the original reusable spool, but the sides are interchangeable.

You can choose between several diameters (12cm, 14cm, 16cm, 18cm, and 20cm).

This lets you shrink the spool without removing the filament, saving space and keeping your storage organised.

With the smallest size, you can fit up to three partially-used spools in the same space as one full-size spool. 

And when you need to load it back into the AMS, just swap the sides back to the 20cm size for compatibility.

To keep the filament secure, this spool uses an integrated clip built into the edge. It provides a simple way to hold the filament without needing separate accessories, although you can still use external clips if you prefer.

IMPORTANT

The 20cm size is mainly intended so that a partially-used spool can be returned to the AMS if needed, rather than for holding a brand-new 1kg filament roll. Using it with a full spool may work, but the design has not been optimised for long-term stability under that weight. Be careful if you intend to use this model with full spools, as the interchangeable parts can be inadvertently unlocked and the filament may fall off.

This caution applies to all sizes, except for the 12cm and 14cm versions, which are safer to use as a permanent solution.

For A1 mini users

The 18cm size pushes close to the build area limits of the Bambu A1 Mini, but it should still be printable and remain compatible with a Bambu Lab filament Refill. I have uploaded a print profile for it, although I have not been able to test it personally.

Material Recommendation

I’ve printed the model in PLA and PETG, and both work great.

You can also use other materials like ABS, ASA, Nylon, or Polycarbonate, but keep in mind that each behaves differently during printing. Depending on the material, you may need to fine-tune your slicer settings or make small dimensional adjustments to ensure the best fit.

Printing Info

If you download the single .stl files or print without the provided settings, please check the print profile description and match those settings in your slicer for the best results.

For the best print quality, I recommend using material support for the bridge-raft interface. This improves surface finish and ensures a precise fit for the locking system. If you are using an AMS, you can include support material; otherwise, set it up according to your slicer software as needed.

Even if you print with support material, I suggest keeping the custom bridges provided, as they’re optimised for the best results.

Custom Bridge:

I’ve added a Support Blocker and small custom bridges to improve print speed and quality around the clip slots. This setup provides cleaner results and better accuracy, so I don’t recommend printing this part using the default bridging settings.

I’ve tested several options, and this configuration works best so far, but feel free to experiment if you prefer.