Bentobox - No Dust design

One of the main reasons why I purchased the Bambu X1C over the P1S was because of the Activated Carbon filter that comes with the X1C.  Imagine my disappointment when I discovered this capability was severely limited when it came to printing ABS or ASA.  The design of the exhaust fan carbon filter (which isn't always on) just doesn't cut it when reducing the toxic gasses produced by printing these materials. Doing research into other options, I saw the Nevermore unit was getting a lot of good press, but it didn't seem like it would be a good fit for the Bambu labs case.  When I came across the Bentobox unit, I was very impressed. Especially with the top down airflow, which is exactly right, at least for the way the Bambu Labs printers print.  

After downloading and printing the model, however, it, I discovered a few things I didn't like. First, the HEPA filter was in the wrong spot.  Since the printer enclosure is already very clean, there wasn't a need to filter before the air before it hits the carbon filter.  I thought about removing it altogether, but since activated carbon media is always fairly dusty no matter which one you get, there WAS a need to filter the air after the carbon filter, to avoid all of that dust ending up in the printer enclosure.  So I kept the HEPA filter, but needed to modify the interfaces on the cartridges to accommodate the new order of the airflow. While modifying this, I reduced the height of that cartridge to reduce the amount of dead air space that wasn't really needed which theoretically reduces resistance and should improve airflow.

The final thing I modified was adding a switch port to the air duct.  I used this switch: https://www.amazon.com/gp/product/B0BK3Y9JJX That size hole should work for a lot of similar rectangular switches though.  I saw someone else posted a round switch option, so you have choices.

Full parts list:

3d parts posted in this Model - fan duct, bento container, hepa container, carbon container, cmag container, infill plates for cmag, and cover

Power Cable guide - https://www.printables.com/model/469451-power-cable-guide-for-bentobox

External parts - 

4x2 magnets - https://www.amazon.com/gp/product/B09SKWWMVM

Switch - https://www.amazon.com/gp/product/B0BK3Y9JJX

Electrical connectors - https://www.amazon.com/gp/product/B07114RK67

Carbon - https://www.amazon.com/gp/product/B0C795JTSM

24v fans - https://www.amazon.com/gp/product/B07L3CT33J

HEPA filters - https://www.amazon.com/gp/product/B0782T7L6P

Input wiring - https://www.amazon.com/gp/product/B07K9R9LBV

AC/DC Wall plug - https://www.amazon.com/gp/product/B099RPD3BB

DC Connector for input wiring - https://www.amazon.com/gp/product/B07QM9W3G7

M3x3mm Heat inserts (x4) for fan installation - these go in the bottom piece

M3x25mm Screws for fan installation - these screw through the fans into the heat inserts

I've posted photos of the step by step installation, the wiring diagram for the switch, as well as the finished product.

1.  Shorter HEPA filter to improve airflow

2. Placement of HEPA filter after the Carbon filter to prevent the dust present in all activated carbon media from entering the lower body of the printer (airflow comes in from the top, hits the carbon filter, then hits the HEPA filter, then exits the bottom).

3. Addition of switch hole on side of fan duct.