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Road to a fanless printhead - DIY radial blower cooling

1. You need a fan to print with PLA.
2. I love PLA.
3. I hate fan mounts.

Fans are bulky and can potentially mess up your thermocouple readings (due to interference from the fan wires). I am a fan of fans in general, but not on a printhead. I tried to design a perfect fan mount several times, but never succeeded. I know there are some nice designs out there, but I haven't had time to try them all out. Those that I did try always had some detail I wasn't happy about. I designed numerous printheads and extruders and whatnot, but it was always those pesky fan mounts that gave me headaches. :)

A year ago I printed out the awesome dremel blower available somewhere on Thingiverse, and that gave me an idea. If I could make a powerful blower, with enough pressure I could supply cooling to the head via a silicon tube, and make a small nozzle for that tube to point the airflow exactly where I want it.

[Again there is blue tape everywhere. I'm sorry.]

 I tested it then with a Dremel 300 and it was blowing like crazy, but of course, no sane person would cool their prints with a Dremel. I needed to find a high RPM motor, but had too much other work at the time, so I completely forgot about that project until yesterday, when I went to a store to buy a cable tester for something, and found a small DC motor with 12V, 0,3A and 11500 RPM. Just what I needed, and at $3.5 I just had to buy it.
[There's also some Kapton tape...]

I printed out some parts, attached the motor and tubing and voila, it works! It is of course unbearably loud, due to the cheap motor, but now I'm on the lookout for a brushless motor, with a bit more power.

[Can you tell I'm not an engineer? :D ]

This alpha version produces a steady stream of very cool air (due to adiabatic cooling I suppose, thermodynamics isn't really my forte). I will try to test this with a print despite the noise as soon as I get my extruder working. I think the low temp of the air coming out could really help cool PLA effectively.

In the next iteration, there will be some messing with converting the PWM signal from UM's fan output to the motors controller, and that is where I would appreciate some help. I was planning to hook up the brushless motor's ESC to an Arduino Nano, and use a small code snippet to convert the output of the PWM to whatever the ESC understands. I have a separate PSU for the heated bed, so the motor will of course be connected to that. The point is that I don't want to mess with UM's electronics too much if I don't have to, and to keep it mostly plug and play.

If anyone has any ideas on how to get that to work, I'm open for suggestions!
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