Work in progress

Large 3D printing filament dryer and storage box, with over the top design specs:

• Max drying temperature above 100°C 🔥
• Air-tight construction (not while drying)
• Ability to hold 4×1kg or 6×700g spools and fit 1×5kg

Hot surface. Hot contents. Ensure continuous ventilation.

We will develop filament settings after calibrating the heat. Check filament manufacturer recommendations before drying. Here is a list of approximate values sourced from resources linked below.

• Drying temperature can vary. It's a generic safe value.
• Duration: The best method is to observe spool weight. After some time drying stops being effective.
• Printing temp: Educated guess. More research needed. Filament will probably cool in the tube between dryer and a 3D printer, but high temperature will prevent it from absorbing moisture while printing.

Filament can form cracks if dryed too rapidly. If a spool absorbed a lot of water, start with lower temperature and longer drying time. The best approach is to take regular weight measurements while drying.

Over-drying can result in filament degrading and becoming brittle. Don't exceed manufacturer recommended drying time. It's better to have some moisture then an aged spool.

Useful generic information about polymers: tworzywa.pl/wiedzopedia/baza-tworzyw

Theoretical glass-transition temperature doesn't look relevant for engineering materials. https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-print-tips-archive/glass-transition-temperatures-not-what-they-seem/

Most dryers don't go higher then 70°C. Resources:

• Glass transition temperature table omnexus.specialchem.com/polymer-property/glass-transition-temperature
• Prusa guide help.prusa3d.com/article/drying-filament_332086
• PrintDry guide printdry.com/how-to-dry-filaments/
• Eibos3D Polyphemus settings shop.eibos3d.com/products/pre-order-eibos-3d-filament-dryer-polyphemus

There are industrial dryers that heat up to 150°C:

• Apium F300; 13 000 zł; Presets visible in the promotional video
  • https://apiumtec.com/en/apium-f300-filament-dryer
  • ABS 60°C 4h, Nylon 70°C 10h
• Purpose FD5; 3200 €; Manual found online
  • https://www.igo3d.com/mediafiles/Sonstiges/PurposeAMS/USER%20MANUAL_FD5.pdf
  • PLA 50°C 4h, PA 65°C 6h

Filament manufacturers recommendations:

• 3DXTECH Filament Drying Recommendations
  • https://www.3dxtech.com/drying-instructions/
  • PLA 65 2-4, PETG 65 2-4, FLEX TPC 65 4, NYLON 90 4, ASA 80 2-4, ABS 80 2-4

Warning! Do not attempt to replicate this without experience with handling electricity. This is not an Arduino project. Working with AC current can kill or maim you.

• ✔️ Ammunition Box 47x21x37cm (NATO size 3)
• ✔️ PTC heater 220V 400W 120x50mm
• 🚚 Thermostat (REX-C100)
• ✔️ High temperature fan (from convection oven)
• ✔️ Steel threaded rivets M10 ≥6pcs.
• ✔️ PTFE tubing & couplers
• ✔️ Alarm light and buzzer
• ✔️ AC IEC socket with power switch and fuse (AC-01-2)
• ✔️ Wire crimper and supplies

Goal is to have a basic version for a price of a cheapest commercial dual-spool drybox. At the time of writing Creality Space Pi can be found on Aliexpress for 366zł.

I was able to get surplus ammunition boxes for 100zł (~$25). I'm not sure what the best heating solution is yet. PTC heater with automatic shutoff at 150°C and with higher power then other commercial dryers have seems safe. Safer then disassembling a hair dryer. It might be under-powered, we will see. It was cheap, at 52zł. I chose REX-C100 for a PID temperature controller. It's extremely widely used, and it makes it very cheap. 48zł including SRR with radiator and a K thermocouple. Fused IEC socket with rocker switch costs 10zł. I also added optional 2x 220V signal diodes, 7zł. Threaded rivets will make installing ports for printing directly from the box very easy. I got both M4 and M10 from Aliexpress for ~30zł. Convection oven fan with motor is will costs 75zł new, ~50zł used. I opted for a new one named C460002A9. Plus speed controller for 8zł. Lastly, alarm light/buzzer for 6zł.

Spent so far: 346zł.

Researching products designed for convection ovens (termoobieg) and DIY meat smoking (wędzarnia) helped. There are no unsolved issues here, just a lot of integration.

• 2024-03-06 - project started, initial purchase - box i.d. 43.5×37×18.5cm
• 2024-03-09 - box has been delivered

• Glass visor
• Alternative gasket material
• Painting inside with heat-resistant paint (white 800°C paint)
• Flament rotation motor (oven roast motor? microwave oven turntable?)
• Humidity sensor (needs to be temperature resistant)
• “IoT” reporting and control
• Load cell for spools
• Klipper/printer integration