This is my design for a heated filament dryer.

It utilizes the heat from the printer cabinet to blow air into an enclosed spool holder, which can be vented outside via a 25 mm hose extension if needed. This system effectively reduces moisture levels, even with the hot bed set to relatively low temperatures, and helps maintain low humidity in the spool holder throughout the printing process.

For filaments that require extensive drying, I recommend running the hot bed at a high temperature with the case fan at full speed until the desired humidity level is reached. It's best to let it stabilize at that level for a while. Once printing begins, the newly exposed filament continues to be thoroughly dried as it uncoils.

I've been using this device for nearly a year, and it's the best addition I've made to my K1. At the end of printing, you can insert a blanking plug into the outlet to seal the spool holder and preserve your filament. The front-loading feature is also advantageous.

I printed the spool boom in Carbon Fibre PETG for strength and resistance to twisting. The window is made of clear PETG. Support is required for the 90° outlet pipe (threaded end to the bed), spool holder, and recess in the cover plate, all of which are on the bed only. The spool boom fits tightly diagonally on the K1 bed, but does fit. No brim or skirt was used for any part.

You'll need to purchase a length of flexible hose with a 25 mm diameter, along with a few screws and nuts from your toolbox for the anti-rotation stop on the boom mount and the knurled knob that secures the boom. The hygrometer was purchased on AliExpress, and the carbon-impregnated foam filter is from aquarium supplies.

To load the filament, simply thread the trimmed end through the PTFE hole, insert an adapter to fit the spool, replace the lid, and lock it in place with the end stop. Then feed the filament through the Bowden tube until it reaches the print head. Insert the Bowden tube into the outlet on the spool holder, and you're ready to print.

I heat my bed to 60°C and run the cabinet fan until the hygrometer shows a desirable level. If you use the plain end stop without a hygrometer, about 15 minutes should suffice.

I hope you find it useful. Let me know your thoughts!

Creality K1 Filament dryer system

0.2mm layer, 2 walls, 15% infill