I designed this to allow me to use quite inexpensive food dehydrators (bought this for 10€) as an effective filament dryer.

This part, printed in PETG gets screwed directly to the base, then makes use of a 608 generic bearing to allow for frictionless unspooling of the filament, to allow feeding directly to the printer.

I decided to print this in two pieces, so you can easily remix or modify the top part to allow it to work with any spool. (Currently tested with eSun, sunlu, Eryone, GST, Bambu Spools, without problem!).

For directly feeding the filament to the printer, just use a M6 coupler, screw it in the plastic case and fit in a PTFE tube up to the printer.

This is the cheapest solution for filament dryer.