5mm spacer plate for Arctic BioniX P140 computer fan

Based on research by Noctua, having adequate spacing between a computers fan and the grill improves both airflow and acoustic performance significantly. Basically it eliminates the high pitch sound made by turbulence hitting the grill/cover.

The ideal sweet spot is around 5mm of space between the fan and the grill. Go over 5mm and there are smaller and smaller benefits to it, and less than that you get the high pitched sound. Airflow is also improved slightly, due to turbulence having time to dissipate before hitting the grill.

Arctic BioniX 140mm fans are remarkably quiet and well performing for their price, but against a computer cases grill it still makes annoying high pitched sounds. So i designed this spacer plate specifically for BioniX P140 fans.

Features:

- 5mm extra space between the fan and the grill.

- Seamless contact to the fan, no unnecessary gaps. Very snug fit. Aerodynamic shape.

- Mostly contacts the rubber parts, to still utilize the factory installed vibration absorbers.

- 0.25mm squeezing space for the vibration absorbing pads, to allow adequate torque on the screws while still maintaining vibration absorbing ability.

- Fits on either side of the fan.

I recommend printing it with 0.4mm nozzle and something other than PLA, due to it having a low softening temperature. I used bambu lab PET-CF, but any PET or PETG or ABS or ASA or other filaments like it will do. Just make sure it can withstand the heat of the exhaust air without softening if you mount this on an exhaust fan. I used 0.12 High Quality preset on bambu lab x1c, 4 wall loops, and 17% infill with gyroid shape. Top surfaces ironing recommended. I recommend not using brim / raft layers for bed adhesion, as they are somewhat hard to remove and this sticks well even without them.

Effect on noise levels:

After installing theese on every fan, the noise levels are so much more quiet. Only the fans motors noise is hearable and at like less than 1200rpm you cant hear the blades making sound from hittting the air because the turbulence they cause doesnt reach the fan grills. I would say this made my computer very much more quiet, maybe like 15 decibels even at like 1000+ rpm. I have 5 bionix 140mm fans in my pc case.

Designing this took like an entire day cuz im new to cad but now my computer is totally silent even under full load. So it was 100% worth it.