Playing with fans

In dabbling with 3D printers, one of the things that I had to deal with is ventilation. Fans.

Fans are used to cool the hotend so that the filament does not melt too far up the heat throat, causing clogs. Fans are used to cool the filament after it has been pushed out of the nozzle so that it hardens and bonds with previous layers. Fans are used to cool down the main control board, especially the drivers for the stepper motors, which can get quite hot.

And fans can also be quite noisy.

The standard fans you usually find on a 3D printer are these 40mm fans. They are 40mm by 40mm, and 10mm thick. They come in both 24V and 12V versions, as these are the common voltages used for 3D printers. There is also the blower type of fan, usually known as 5015 fans as they are 50mm in diameter and 15mm thick.

Fans, however, are available in other dimensions too. Recently, I have been playing around with 80mm fans. These are 80mm by 80mm; thickness can be 10mm, 15mm, or 25mm. What is amazing is that those 80x80x10mm fans are really quiet. They push out more air, but generate less noise that the 40x40x10mm fans. And so, I have been using them for my case fan (to cool the control board) instead of the usual 40x40x10mm fans. Super reduction in noise. I recommend them to everyone who wants to have a quieter setup. It is probably the reason they are used in computers too.

The 80x80x15mm fans push a lot of air too, but also sound a lot louder. To me, they are great as generic fans, like if I need to make a small desktop ventilation fan and don't mind the noise.

Blower type fans are also found in other voltages too, like the 5V ones below.

Back to the sound level issue. There are people out there who would spend the extra money (like, 5 times the money) for quiet fans like the Noctua. Unfortunately, I do not have that kind of money, so what I do is to get a fan rated for a higher voltage, and use it at a lower voltage. For example, I use a 12V fan to cool my Raspberry Pi, running the fan at 5V. It pushes out enough air to keep the Pi cool, but generates a lot less noise. This is a bit difficult for 24V setups, since 48V fans are not as readily available. Still you can always connect a power resistor in series with a 24V fan to lower the voltage across the fan; this waste energy, though. And make sure the resistor is rated for that kind of heat dissipation; a 2W resistor should be enough, but those 1/8W or 1/4W resistors we usually use for breadboards will NOT do.

Conclusion:
- Use 80x80x10mm fans for cases and such to cool the control board.
- Use a lower voltage to drive the fan (5V for 12V fan, or 12V for 24V fan; doing the reverse will overwork the fan, generate lots of noise, and shorten the life of your fan dramatically).