HEPA filter for 3d printer enclosure.

The 80mm is the most usual fan of the last 20 years on PC and electronics devices, this Hepa filter is designed to take profit of old fans. The 80mm standard fan have a nice performance airflow against air pressure.

It also can be used as you want.

Wen you think about put some fans inside a 3d printer enclosure, on recycling configuration thee are no problems, hot air stills hot inside the enclosure.
But when you think about an exhaust configuration it pulls hot air from the enclosure, and intakes new fresh air, you need take care of how much air can pull from inside, whitout drop temperature.
Take care of this fact,
The most reliable option is mount a temperature relay to stop the fan when the temp drops bellow target.
Or just adjust the fans on low rpm using a DC-DC or PWM module if the fan has this feature.
Aswel if you 3D printer main board have free GIPOs, you can set up a temp prove and a relay to control by the printer.

Designed thinking on the three main configurations, free exhaust for recycling the air inside the enclosure, Connected to 80mm duct, or mount whit 90º adapter to exhaust the air thru the enclosure.
All printable parts are designed as the same shape and are compatible.

• Short exhaust, just to avoid fluctuations on recycling setup
• Long exhaust, for connect whit 80mm duct.
• 90º exhaust, for mount directly on the surface of the enclosure.

How much fans i use?

When you use axial fans to pull air from a filter, the problem is Axial configuration don't have to much air pressure, and when the filter starts get stuck the thread-down on the air flow is to high.
But you can stack two or more 80mm fans, it works best if they are equal, and then the amount of m/3 is the same, but the pressure inside rises up. Its important use the coupler included on the design to avoid the fluctuations and get the best performance.

The HEPA filters for Roomba series 800-900 are cheap and easy to buy on internet, and the double configurations extends the time between replace.

All screws are M4, and all holes are 4.5mm

Thinking about this design, i will make a Buterfly manual valve some day: https://www.thingiverse.com/thing:4216080