HEPA Filter for 3D Printer

thingiverse

**Air Scrubber for 3D Printers** The *Prusa i3 MK2S* is a great printer especially for the hobbyist or light industrial desktop user. That having been said it is a raw printer without a lot of accessories that would make it a great printer. The is the first in a series of accessories that I designed for the *i3*. The others are: - Enclosure https://www.thingiverse.com/thing:2396990 - Spool Holder https://www.thingiverse.com/thing:2398480 - OctoPrint Print Server https://www.thingiverse.com/thing:2401423 This accessory is intended to remove VOC and Ultra Fine particles from the enclosure housing the printer. 3D Printers produce VOC and Ultra Fine particles as a unwanted byproduct of melting and extruding plastics. See recent study by Illinois Institute of Technology and The University of Texas at Austin among others: http://pubs.acs.org/doi/full/10.1021/acs.est.5b04983 Additionally some filaments emit a noxious odor when heated to high temperatures. Originally the plan was to exhaust 100% of the filtered air either inside the enclosure (moisture elimination & heat retention) or outside the enclosure if internal ambient temperature was not a concern. The exhaust configuration could be changed prior to each print. After several experiments it was determined that a portion of the filtered air (about 40%) should be recirculated and the remainder ported outside the enclosure. By porting a portion of the filtered air outside the enclosure, the pressure inside the enclose is lower compared to ambient. This insures that no unfiltered air escapes from the enclosure during printing. The current *Nozzle* design accomplishes this. Included is a *Restrictor* plate to change the mix to 50/50% should the 40/60% cause the enclosure temperature to drop too much when printing ABS or other filament types that require a high stabilized temperature. The design includes a *Extended Grate* that can be used to divide the chamber into two sections, one for silica (drying) and one for activated carbon pellets (VOC filtering). In practice it was found that the *Activated Carbon Pellets* provided adequate anhydrous characteristics and silica was not needed. Should your experience vary, simply insert the *Expanded Grate* at an appropriate location in the chamber. Fill the section closest to the *Fan* with *Activated Carbon Pellets* and the other with Silica. This insures all the air is filtered for VOCs. This assembly is based on a design by RJ_Make that incorporates a HEPA filter originally designed for iRobot sweepers and a chamber which contains _Activated Carbon Pellets_. This remix differs from the one by RJ_Make: - Screws replace rubber bands to hold the various parts together, - Part count reduced by combining several parts into one, - Fan exit *Nozzle* has two outputs - One for overboard and one to recirculate filtered air within the enclosure, - Adds *Exhaust Tube* from *Nozzle* to *Enclosure Grommet*, - Includes *Enclosure Grommet* and optional *Restrictor*, - Specification for *Fan* and optional *Speed Controller*. 7/12/2017 Update: Removed file "Chamber Top" as it is no longer needed. 1/7/2018 Update: - Restore chamber *Baffle*, - Modify *Chamber* to capture the *Baffle* below filter flange in order to create space between Filter and *Baffle*, - Modify *Filter to Motor* and *Expanded Grate* by eliminating top several rows of holes to force more air to pass through activated carbon pile, - Support for alternative *Fans*. 3/5/2019 Update: Added Strengthened Mount courtesy of beikeland.