Filament Dryer Not Hot Enough? Build Your Own with an Old Air Fryer
element14 Presents' Milos Rasic converted an old air fryer into a high-performance filament dryer that will get as hot as you like.
Your 3D printer’s filament needs to be dry (free of moisture absorbed from the surrounding air) to perform properly. Effects vary based on the specific filament material, but absorbed moisture can cause everything from poor print quality to complete print failure. Most filament materials can dry properly at around 60°C, which is what consumer filament dryers tend to target. But some filament materials need much higher heat. If you want to print those materials without spending a lot of money, follow Milos Rasic of element14 Presents' guide to build your own high-performance filament dryer using an old air fryer.
As you’re undoubtedly aware, air fryers became incredibly popular a few years ago. As a result, thrift stores, secondhand stores, and dumpsters are absolutely overflowing with the things. And they make good candidates for filament drying: they get very hot (175°C at a minimum) and circulate the hot air. But you probably don’t want to just throw your nice, expensive filament into an unmodified air fryer, because it won’t have very precise temperature control or timing. The conversion performed by Rasic adds those features (and more) to make the air fryer safe and effective to use as a filament dryer.
To achieve that, Rasic integrated hardware capable of controlling the air fryer’s heating element while precisely measuring the air temperature. The hardware also controls the air fryer’s fan to circulate the air.
The key component is an Arduino UNO R4 WiFi board. It controls the air fryer through three relays: one for master power, one for the heating element, and one for the fan. It monitors the air temperature through a DFRobot DFR0558 temperature sensor. This system is far more accurate and precise than the air fryer’s original mechanical thermostat.
Even better, Rasic was able to create a really nice control and data visualization interface using the Arduino Cloud service. It lets the user set a target temperature and a drying time, which the air fryer will then maintain. It also provides comprehensive data, so you can visualize, for instance, the heating and cooling cycles as it attempts to maintain the target temperature. A more sophisticated PID (Proportional Integral Derivative) control algorithm might level that out, but that isn’t necessary for an application like filament drying — so long as the temperature doesn’t get too high for a particular filament material or its spool.
For roughly the same price as an off-the-shelf filament dryer, you could follow Rasic's guide to build your own filament dryer that will perform much better