3D-Fuel Spool Notch And How To Cover It

In late fall 2025, we started using a new 1kg spool that uses 29% less plastic and has a notch to enable automatic winding on our USA filament manufacturing lines. This spool was tested extensively on the Bambu Lab AMS units, similar style units from other brands, and in a variety of filament dryers.

Download and print the spool ring cover here.
 
In those units, most of which use rollers ~8mm in diameter, the notch worked without any interference on the rollers.

 
Unfortunately, some dryers and edge-based spool holders, like the Creality Space Pi, use a much smaller roller of about 4mm, which CAN cause interference in the notch and lead to the spool becoming misaligned or getting stuck, triggering an extruder motor overload error.
 
We have developed a lightweight, fast-printing spool cover ring designed to fit the notch perfectly and clip into place easily (I know, we all hate spool rings). It keeps the overall spool diameter small enough that the spool with the rings installed also still fits into the AMS and AMS 2 without any interference or dragging. 

Download and print the spool ring cover here.
 
The ring prints using less than 7g of filament per ring (we recommend printing in PETG or Pro PCTG so that it will withstand the higher drying temps of 65 °C when drying PCTG) and prints in less than half an hour per ring.
 
In December 2025, we switched to this same style spool, but in a version WITHOUT the notch, so this is a short-term challenge to overcome.

We are currently evaluating a different notched spool design to enable an automated winding sytem, but we do not expect those to go into production until Summer 2026.
 
Thank you for your understanding and flexibility as we work to keep our USA production costs in line.