This is an attempt to make my own filament dryer. In the end it's not really cheaper than buying one (e.g. SUNLU) but where is the fun?

The filament dryer offeres enough space for two 1kg filament spools. No support needed for any of the parts.

You should use filament that can withstand at least 70°C as the heater at the side of the box gets hotter than the air measured inside. In my case, I used ABS+ for all printed parts.

For the wiring, please have a look at the two pictures that show the overall wiring and the connection of the temperature controller. I'm not an electrician but feel free to ask questions if you're stuck.

BOM:

• W3230 Mini Digital Temperature Controller 12V 24V 220V (https://de.aliexpress.com/item/4001226880181.html?spm=a2g0o.order_list.order_list_main.42.69415c5fS5lNqE&gatewayAdapt=glo2deu)
• 12V 120W PTC Heater with Fan (https://de.aliexpress.com/item/1005005066986485.html?spm=a2g0o.order_list.order_list_main.27.69415c5fS5lNqE&gatewayAdapt=glo2deu)
• DC 12V PWM fan/Motor Controller Board (https://de.aliexpress.com/item/1005004545212182.html?spm=a2g0o.order_list.order_list_main.37.69415c5fS5lNqE&gatewayAdapt=glo2deu)
• 12V 20A 240W AC/DC PSU
• PSU switch with 15A fuse (optional but highly recommended)
• 2x Bowden push fitting connector M10/6mm (optional if you seal the holes in the lid)
• 4x 100mm Ø8mm linear rods
• 8x 608 ZZ ball bearings
• 6x threaded inserts M3x5.7
• 8-9x M3x6 round head screws (6x for body parts, 2-3x depending on your PSU)
• 1x M3x10 round head screw, M3 washer and hex nut (for lid)
• 2x M4x15 round head skrews and 2x M4 hex nut (for heater)

Unless you replace the stock fan on the heater by a 4-pin 60x60 fan, the fan controller only works as a switch. With a 4-pin fan the fan speed can be controlled.