Low noise Activated Carbon and HEPA exhaust filter (with optional EnXlosure frame)

After using my first exhaust filter for half a year now I noticed that I had still to cough quite often when entering the room. Turns out that a HEPA filter is really something which should be used in addition to the activated Carbon. I tried many filters which were proposed here in this (and other) forums and none of them was really doing what I wanted. Too noisy, not enough pull, didn't look nice, and so on. So - I finally took a lot of ideas and came up with this version for my own (or your) use and added it to my EnXLosure. That being said - this filter works of course for all other printers, enclosures or use cases.

I did do now several PLA prints with the upper EnXlosure closed so that only the fan would pull out the exhaust fumes. It turned out that I do not smell much (any?) PLA anymore when printing and the coughing / sneezing has stopped as well. To further prove my point: I have printed PLA for an entire day, not opening the window, not running the Dyson. The result can be seen in the attached screenshot. Notmally it shoots through yellow when the window is closed pretty much immediately. Here - nothing can be seen! So it works!

Changes to my original design:

1. A more powerful fan which pulls the air instead of pushing it
2. A filter cartridge containing
   1. A HEPA filter
   2. An activated carbon filter with grains

I did do a deep analysis of available fans (and there are many) and found these to be the best fit:

• Noctua NF-P12 redux-1700 PWM - 70CFM, 25dB
• Wathai 120mm x 25mm 12V High Pressure CFM Fan - up to 114CFM, 44dB
• Scythe kaze Flex II 120 Slim PWN Premium Slim PC Fan - up to 90CFM, 28dB

I was going in the end with the Noctua as I like it silent and the Scythe had some negative comments which made me shy back.

Note:    

• If you are using a PWM filter and have only 12V, you can look up the right pins to use here.
• I also considered 14cm fans which could have easily be done. But I was not sure if this would have helped much. So I did not add that. If someone sees big use for it I can be convinced to make another version for that.

Additionally you need

• 8 x M3 
• 4 x 45mm M3 screws
• 4 x 30mm M3 flat head screws
• 8 x 6x3mm Magnets 
• HEPA filter (comes in a 4 pack, but also available in single units)
• Activated carbon granulat

The EnXlosure top is a modification of my other one from here.

You should print the following pieces from PETG:

• Filter bottom
• Filter Cartridge
• EnXlosure top (if you need this)
• Optional: Filter top

The other pieces would be potentially be fine as PLA, but PETG is also fine. 

Many thanks also to @thrutheframe for allowing to put in an enlarged version of his carbon filter cartridge!