Laser engraver HEPA and carbon air filter

3 part 3D printable HEPA and carbon filter assembly designed to fit on the build plate of a mid-sized printer (228mm cubed build area and up.) Requires one 6mm bolt 120mm long, one 6mm fender washer, one 6mm hexagonal threaded insert (or a slightly longer bolt and you can use a nut and washer instead) some 4 inch dryer duct with band clamps, a large (9 inch) band clamp for the housing and a 4 inch inline duct fan.  The filter is rated for up to 260 CFM, so don't exceed that when you choose a duct fan. 

Designed to use a replacement filter for the LEVOIT Vista 200 air purifier, which has a pre-filter, a HEPA filter, and an activated carbon filter built in. This filter also has a foam seal at the top and bottom, so it shouldn't need any further sealing. I also used a piece of carbon filter mat wrapped around to give it another layer before the HEPA so it doesn't clog as quickly and it has an extra layer of activated carbon to reduce odors a bit more. 

After testing for a few hours with my Bambu Labs H2D, which has an exhaust fan built in, this filter removed all visible smoke and particulate and greatly reduced the burning wood smell in the shop. I make no guarantees that it will remove enough of the smell to keep anybody but me happy, but I was mostly looking to stop the smoke from scaring my coworkers. :) 

To assemble, put the bolt and fender washer as pictured through the filter cover and attach the filter securely to the Air Housing B part, using either a nut and washer or the recommended hexagonal M6 threaded insert. Use the large band clamp to hold Air Housing A to Air Housing B tightly. The fit should be tight enough once it is tightened down that you won't need additional sealing, but I left enough of a gap to allow for different printer accuracies. (If I make another version, I'll add a small lip inside housing A to keep B from sliding too far in. I'm including STEP files, so feel free to modify as you require. I was able to assemble without much trouble as it is.) Use the small band clamps to secure Housing A to a 4 inch duct to the laser and Housing B to a 4 inch duct to the 4 inch duct fan.

Because my laser has an exhaust fan, it may have better results than one without, but the duct fan seems to be enough to move the air through pretty well. I put the duct fan after the filter so it would always pull the smoke through the filter instead of pushing it into the housing and possibly forcing it out elsewhere. You can, of course, add more ducting after the fan to send the exhaust outside or into your coworker's office. :-D 

These are the filters I used:

Vista Replacement Filt-er Compatible with LEVOIT Vista https://a.co/d/8VWgPi9

PUREBURG Carbon Filter https://a.co/d/gWy6svC

This is the hex threaded insert I used:

Aluminum Twist-Resistant Hex-Shaped Inserts for Plastic, M6 x 1 mm Thread Size | McMaster-Carr

Thanks for checking it out! :)

Added 6/5/25: The picture of the filter is after several hours of use, it definitely catches a lot of particulate. :) 

Added 6/9/25: After several more hours of laser cutting, the filter did start to clog enough to allow some smoke through, likely around the foam seals on the filter. I removed the filter and blew it out with compressed air and it worked again, but the filter will need to be replaced soon. Definitely not a full replacement for a heavy duty filter setup for a full time laser shop, but good enough for lighter use and for filtering large particulate before you vent outside.