Core one integrated heated dry box/dryer

Overview:

This turns the core one's filament holder into a heated filament dryer. Four main parts: the door, the heater, a new filament holder, and a magnetic clip for heater power cable to make space for the heater.

From my testing, the dryer gets to around 50C in a few minutes. Unfortunately, it's too weak to heat the printer chamber. 

The dryer is not airtight as I wanted the hot moist air to slowly seep out. Should still work fine with just desiccants inside. Add thin EVA foam tape like this under the magnets if sealing is a concern (not tested)

Update:

12-9-25: Added step files and Onshape link in file note. Be aware the step file includes helper models not meant to be printed

BOM:

• Heater:

1. A SUNLU S1
   The heater is basically a SUNLU S1 dryer jammed into the filament holding space. No need for extra electrical components nor soldering. Although some extra wires might help to position the fan.
   Other SUNLU dryers may also work. I used S1 because it was on discount, and it won't wire grid power into the printer. But the interface is truly awful. If you got other dryers to work, please post your make. Thx.

2. Four 18mm x 5mm ceramic magnets
   The dryer gets to around 50C. Numidian magnets might get demagnified

3. M4 screws and nuts x 4
   Can't remember if SUNLU S1 had these

4. M2 screws x4
   Again, can't remember if SUNLU had these

5. M2 screws x2
   To attach the two parts together

• Door

1. A 12'' by 12'' Plexi glass
   I just bought mine off Amazon

2. M3 screws and their nuts x 12. Around 16mm
   This is for the door
   I'm not entirely sure about all the screws length I've used. 16mm is tha max
   The crank uses 6 on each side. You may not need the nuts inside the printer tho
   You may get away with shorter ones, like 12mm, on some parts

3. M3 screws x 4. And their nuts. 12mm
   This is for the cranks
   16mm will also work but 12mm is the minimum
   Nuts are installed the same way Prusa does it

4. M3 washers x 12. Optional
   This is for the cranks
   You can see them in the photo. Without them, the screws may work itself out over time.

5. 6mm x 2mm round magnets x 12
   There're holes for 24, but 12 should hold the door up.
   Install them like in photo. Top and bottom needs 4 each and the side is mostly for sealing.

• Holder
  Printed. Only need it if you use the heater.

• Heater clip
  1. 6mm x 2mm round magnets x 1
  Optional part. Just make sure you insulate the power connector otherwise. 

Notes:

Everything is one stl. Spilt it into objects with the slicer and choose what you need.

Assemble like in photos. Here's the 3d model if it helps.

All four door frames are the same.
All cranks are the same.
The part connecting the door cranks to the printer is mirrored on each side.

Can reach 50C inside so print with something heat-resistant. I used ASA

Print the spool holder tough. I printed 5 walls ASA, and it doesn't flex at all with 1kg spool. 

I made this before Prusa released the new spool holder. The Plexi glass is about 5mm away from the panel, so should still work. Not tested. If you tried this box with the new holder please leave a comment. 

The heater PCB has two small printed buttons. Careful not to lose them

Door feels cheap. It is cheap but just pointing it out.

I may run this description through AI for grammar check later. Whenever I can be bothered. 

That's it. Please post makes. And don't touch the heating plate when it's hot.