What are the sizes and weights of your spools?

Notched Spool Ring Cover File

For 3D-Fuel materials, we primarily use two spools in the US: 1kg and 4kg. The material for these spools is High Impact Polystyrene.

NOTE: We've used an AMS-compatible spool design for our 1kg spools since October 2023. As of April 2025, effectively all of our inventory is on AMS-compatible spools unless otherwise mentioned.

Our "old" 1kg spools fit in the Bambu Lab AMS but did not allow the lid to fully close (it wasn't be able to latch shut).

The new 1kg spool enables you to close and latch the Bambu Lab AMS fully. It is also compatible with all 4 positions on the AMS Lite.

November 2025 Update: We have moved to a new AMS-compatible spool that uses 31% less plastic and features a smaller-diameter core. This helps avoid interference between the filament on the spool and the inlet on the AMS systems.

Spool Notch Cover Ring - Download

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.

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, and triggering an extruder motor overload error.

This lightweight, fast-printing spool cover ring (I know, we all hate spool rings) fits the notch perfectly and clips into place easily. It keeps the overall spool diameter small enough that the spool with the rings installed also still fit into the AMS and AMS 2 without any interference or dragging. 

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 65C when drying PCTG) and prints in less than half an hour per ring.

We are currently redesigning the notch to accommodate the smaller roller diameters, so this is intended to be a fix to bridge the gap until the redesigned notch is integrated into our spools.

We have also temporarily switched to this same style spool, but in a version WITHOUT the notch, so this is a short-term challenge to overcome.

Thank you for your understanding and flexibility as we work to keep our USA production costs in line.