Voron Silent Wings Fan Mount

Demo:

I don't know how audible they are on the video, but I cannot hear them spin at all. The noise at my desk while printing used to be around 55dB; now, it's under 40 dB.

BOM

• SILENT WINGS PRO 4 (https://www.bequiet.com/en/casefans/3705), at least one
• “fan_mount.stl”, “fan_mount_mirror.stl” printed parts
  • “rail_octopus_only_190mm_x2.stl” short rails for a single fan for octopus
  • “rail_octopus_and_pi_290mm_x2.stl” longer rails for 1 or 2 fans across octopus and pi
• “feet_riser_x4.stl” to lift the printer a bit higher for better air intake
  •  M5*20 x4, one for each foot

Assembly

Print with standard voron settings or whatever works for you, no supports.

Press the rails into the mounts.

Fans prep: swap the corners for smaller ones:

Find rubber fasteners in the accessories and attach the fan to the rail (logo facing away from the mount):

The fan should be able to slide along the rails.

Wiring

The fan has 4 wires: 2 power, 1 PWM, 1 tachometer. If you want to be able to control and monitor the speed, there is a guide for that: https://www.nicksherlock.com/2022/01/driving-a-4-pin-computer-pwm-fan-on-the-btt-octopus-using-klipper/

I'm using only 2, reusing jst connectors from the stock fans

which makes them spin at full speed all the time. This is fine – each fan has a speed selection slider with 3 positions, and using the slowest speed is enough to keep things cool (see Performance section below).

IMPORTANT: THESE ARE 12V FANS. Make sure you set the jumper to 12V on your octopus pin. 

Lastly, mount it to the din rail:

Feet riser

The fan doesn't work well when the intake is close to the surface. My solution – a riser that lifts the printer just enough:

It doesn't look pretty, but it does the job and you get to keep the rubber feet. Just sandwich it in between the rubber and the z-drive and use a longer M5 fastener. 

Performance

I did some very scientific measurements (a thermistor taped to the tmc2209 heat sink), and to not bore you with the details, here are the key points

• A single fan on the lowest speed is as good as two stock side fans. After an hour of printing, the AB motor drivers stayed under 35C and pi under 40C (ambient temp at my place is ~27C)
• A two-fan setup on the lowest speed doesn't improve the cooling significantly (-2C for drivers, -3C for pi) compared to a single-fan:
• A two-fan setup on the second speed removes a few more degrees, but now you can hear the fans spinning (a little)

I suggest going with a single fan on the lowest speed placed in between Octopus and Pi (so get the longer rail and slide the fan). Adjust the speed if needed.