Sometimes, when using the CFS with filament spools made of cardboard—like Creality Hyper PLA—the spools might already be somewhat damaged, or they may initially appear fine but become warped or bent during use, resulting in feeding jams. The last time this happened, I was printing a part that took more than a day, and I lost the print because the Creality Hyper PLA cardboard spool bent, causing a filament jam. My printer managed to print an entire layer in mid-air before detecting the issue and pausing—but by then, the damage was already done.

I searched for alternatives to replace these cardboard spools, but the options I tried either didn't work with the CFS or didn't meet my expectations.

This particular design has been thoroughly refined and tested. It may seem simple, but the CFS imposes certain constraints that required several iterations to meet. :)

Recommendations: Print at 100% infill and at a slow speed, particularly just before starting the threaded section. The thread fit is intentionally tight to ensure a secure and rigid connection once screwed together. This means some force is required during installation, making it critical that the part be sturdy. So far, I've printed these only in PLA, but using stronger materials would probably deliver even better results.