Advanced Filtration Dumptruck
The advanced filtration unit is probably OK for somebody that needs it most of the time, but it's just an annoyance for those of us who mostly print PLA and PET-G. There are schemes for moving/removing it, but I thought it would be nice to not have to deal with it at all. The basic idea is it gets moved to the top of a box. The box has a door like a dump truck. When the advanced filtration unit is enabled, it tends to hold the door closed by suction. When the standard fans are used, they blow the door open and bypass the filter. Better airflow and you're not wasting the expensive HEPA filter when you don't need it.
Understand that this is a first shot at a prototype and you take full responsibility for every possible outcome if you build it. I'm hoping the community will decide if it's good or bad and will improve things that need improving or at least suggest improvements. One thing that it needs is a counterbalance for the door. Attaching about 50 grams to the top of the door makes it easier to open and improves airflow. Works as-is but works even better with a small strip of adhesive wheel weight or a brass bar.
I don't have a great record of sticking with a project, so I've zipped the FreeCAD files and everything else you need in the attachment. I tried to conserve filament (PET-G) but a smart person would increase the perimeters of the box to maybe 3 or 4. Small metric hardware has to be ordered in the US, so I used the M3x10 SHCSs that I had a drawer of. Shorter screws would save thickness of the base, but about 3 mm of engagement with the Core One is needed. Use whatever machine screws or sheet metal screws you like to attach the filter unit to the top of the box. I kept the infill on the door to a minimum to reduce weight. You might get it even lighter by exposing the pattern and not having an outer layer at all but use a symmetric pattern to prevent warpage. The door pins are 0.0625" dowel pins. Adjust to suit what you have but keep them as small as possible for low friction. I thought about printing pins on the door but that would have been a mistake.
Last notes. The door lifts off so if you need the last little bit of air flow on a hot day, just lift it off and set it aside. Don't put the printer up against a wall with this attachment!
Enjoy!
RE: Advanced Filtration Dumptruck
Love this idea @conrad-2
Needing to filter infrequently is the very reason my advanced filter is still new and unused in the box. I ended up grabbing a Vento that snaps into place & removes with magnets because the available solutions weren't easy to use in the space I have, and still restricted airflow when not filtering - unlike this which shows a lot of promise I think.
RE: Advanced Filtration Dumptruck
Some additional thoughts.
There's room to make the door maybe 6-7 mm taller. That would allow a few pockets to accept coins for counterbalance. I've done that on other projects. A US nickel is 5 grams and 2 mm thick, so I bet five pairs of them could fit. Lowering the mass of the door would still help a lot and I'm sure with a bit of fiddling it could be half what it is. I have a machine shop and can easily add a metal weight bar across the top, but I'm trying to find solutions anybody can do.
For times when you don't want any flow resistance at all, the door has a storage position. Just turn it upside down and set it back in the bearing notches, leaning against the filter housing. Just remember to put it back when you need the filter unit.
If the hole size is taken to a minimum, the bearing pins could be ordinary straight pins with small heads.
RE:
Another good candidate for the pins would be ordinary small brads (nails) from the hardware store. Keep the heads off the pivot points or just file them off.
A benefit I didn't mention is the HEPA filter is now fully exposed, so should work a bit better, compared to being pushed up against the perforations on the rear plate.
RE: Advanced Filtration Dumptruck
Here's a version of the door that's a bit thinner, 2 mm, and uses 7/8" x 17 gauge wire brads for pins and US nickels for counterweights. Works well and I'm going to call it done and use it for a while. Surprised there has been more interest in this, given the complaints about the filtration unit.