Hello everyone,

I’ve designed an adapter that allows the Auxiliary 120mm blower fan on the Creality K1C to function as a carbon/HEPA filtration unit. Since I don’t frequently print with PLA, this modification is particularly useful when working with materials such as ABS or ASA, which are known to release potentially harmful fumes.

The filter assembly prints in four parts:

• The lower section houses the fan. The fit is currently very tight, and I’m in the process of developing a revised version with more forgiving tolerances to address this issue.

• The upper section attaches to the lower body using four M4 screws. There is space to install heat-set inserts if desired, although I have not yet done so during prototyping.

• The mesh component should be printed with zero walls and no top or bottom layers. I used 25% gyroid infill to prevent the activated carbon pellets from falling into the fan.

• The lid secures to the top using four M2 screws.

The HEPA filter used in this design is from the Dreame X40 robot vacuum. To ensure a proper fit, the two small tabs on the front of the filter will need to be trimmed. I purchased mine from the following eBay listing: https://www.ebay.com.au/itm/395555578303?var=664294682621

Note: that this is still a work in progress. While it is functional, there are a few issues I am currently addressing:

• Fan fitment: The fan is a very tight fit in the lower housing, requiring significant force to install.

• HEPA filter clearance: Although the filter can be inserted, the tightness causes the sides of the print to bulge slightly, making it necessary to compress the sides to properly screw the lid in place.

• Fan inlet alignment: The inlet is visually misaligned—it is centered based on the 120mm fan’s dimensions, whereas the actual inlet is slightly offset to the left. This does not affect performance but is aesthetically noticeable.

Note: I printed this filter in transparent Sunlu PETG. For the intended application—particularly when printing materials like ABS or ASA—the filter housing should be printed in PETG, ABS, ASA, or any other filament capable of withstanding the chamber temperatures required for those materials.