Centrifugal Fume Extractor | Carbon + HEPA Filter

This is a fume extractor containing activated carbon filters, a HEPA filter, and a coarse filter to remove harmful particles and odors from the air. I've decided to go with a centrifugal blower fan, which is better at creating the negative pressure needed to force air through thick filters than a standard axial fan. I've also designed this extractor to incorporate a plenum chamber, which is an enclosed, air tight space in between the fan's intake and the filters. This chamber creates a large, stable volume of air before it hits the blades, which is intended to decrease turbulence and increase fan efficiency. While being primarily designed for filtering solder fumes, this extractor can be used for other low risk applications as well, hopefully fulfilling Maslow's lesser-known basic human need for fume extraction! If you have any improvements or suggestions, please feel free to let me know! Its okay if it sucks too, (its supposed to do that ;) ). Materials & Links: - 120mm Blower Fan

- 6" x 6" HEPA Filter

- Activated Carbon Filter Sheet

- Coarse Filter Sheet

- Power Switch

- DC Barrel Jack

- 12v 2A Barrel Wall Plug

Instructions: - Cut two 155 x 155mm squares out of a activated carbon filter sheet, and one out of a coarse filter sheet. - Cut a makeshift gasket to create an air-tight seal where the fan meets the body; you can do this with any excess coarse filter sheet if you'd like. - Attach wires to the switch (you can use some of the wire that comes on the fan, as they're pretty long). - Glue the switch and plug into the holes in the back. - Wire everything together. (note that the switch I used in this design has a cool built-in light, but is unused in this model) Connect the positive wire from the barrel jack to the "supply" terminal, and the positive wire from the fan to the "load" terminal. Connect the negative wires together. - Screw in the fan with the included screws (or use your own 4mm ones). Be sure to sandwich the gasket in between as well. All wires are designed to be hidden in the - compartment right below the fan. - Install both sheets of the activated carbon filters (2x), then push in the HEPA filter, and finally the coarse filter on top. - Install the cover to keep the filters in place (should be a pretty snug fit). You can try adjusting slicer tolerances or add tape if its too tight or too loose. - Install the fan duct into the exhaust of the blower fan. - Add rubber or felt feet to the bottom (optional).

Printing: - Use a 0.2 - 0.15mm layer height. - 3 wall loops for better hermeticity. - Print the exhaust duct on the flattest side. - Print with the filter side up to minimize turbulence in the plenum chamber. - Enable build plate only tree supports, because they're freaking awesome. - I recommend using PETG filament for heat tolerance next to soldering irons, but PLA should work just fine as well (just be sure to choose cool colors ;) ).

Iterations: - V1: Used a normal 65mm axial fan. - V2: Changed design to use a 120mm centrifugal blower fan instead. - V3: Increased space in filter housing for an extra sheet of activated carbon filter. - V4: Adjusted front cover to press against the filters and add a more friction fit. - V5: Created and optimized an exhaust duct to direct air away from the intake. - V6: Final polishing, I just love fillets.

Important Disclaimer! This filter has NOT been scientifically tested, so don't go using it in a lab to filter bromine vapors or something. It should NOT be considered protection against hazardous gases or vapors unless the filtration performance has been specifically tested for those substances. Thanks and Happy Printing!