Enclosure fan and filter (for cheap zippered enclosure)

Need to filter out the nastiness of plastic fumes and keep an enclosure cool enough for PLA? Here's my solution. This was designed in OnShape. Feel free to open there and change any tolerances or sizes you want 

Design:

This fan and filter housing is designed to fit the cheap zippered enclosures with the side access flap that measures 250mmx170mm. I wanted to have a known brand of HEPA filter so I went with the Honeywell size “R” (260x165x40mm). I found some that include a carbon pre-filter and added about 3mm clearance to accommodate the extra media. The fan mount should be fairly standard to any double 120mm fans. The ones I have are already joined in the middle by metal brackets so I only added holes for the outer corners. The filter just drops into a slot for easy swaps and removal. My bed can't accommodate a print this long so I divided the parts up using a basic dovetail. The fan bracket is sturdy enough that the majority of the strength between parts will be from the printed parts connection to the fans. Use some glue at the mating surfaces to keep things from falling apart so easy. Some sanding with a triangular file makes it easy to adjust the dovetails if it is too tight.

The print stays in the opening by simply clamping the edge of the opening. This results with the fan on the outside of the opening and the filter on the inside (to help minimize foot print inside the enclosure).

Tolerance designed in:

My printer usually needs about .2mm of “tolerance” between dovetail/puzzle piece type connections. I've designed the horizontal cuts to give a 0.2mm gap to help with fitment. I've included a three piece tolerance test if you want to print a test and fine tune slicer settings to get a good fit as designed.

My print settings:

Used a standard 15% infill, 0.2mm layer height, 3 wall perimeters, and walls print inside to outside (changing this may change how parts fit each other).

The fan bracket is printed flat. Both pieces should fit on the build plate if you arrange it well.

The filter bracket is printed with the left and right sides on the build plate with the dovetails pointing up. If I had spent more time tinkering with the design, there may have been a way to also print these flat to assist in overall strength, but I didn't want to print with supports for the edges that hold the filter in place. This is also why the walls may be thicker than absolutely necessary.

Hardware Needed:

Four m4 bolts and four m4 nuts. Mine were 45mm long, but you may need to adjust as needed to fit your fans.

Parts used:

• Enclosure: If you're like me, you don't have time to make a custom enclosure and don't want to pay more than your printer for a nice one. I ended up with this: https://a.co/d/1iRvWlM It's basically a clone of the creality.
• Fans: Here is the ones I used: https://a.co/d/3tJqRvi Comes with North American plug, fan controller, and the screws and bolts I used to assemble mine
• Honeywell Type R HEPA filter and carbon pre-filter: https://a.co/d/gLs7l80 If you search for a type R or size R HEPA filter, there are no-name brands available. These happen to fit some other air purifiers we already own and I trust that they actually are HEPA rated.
• I used some cheap PLA to print