Unfortunately I have not seen mode 3 yet, only 1 and 2. When printing filaments that dont require chamber heating its always bypassing the filter. In Orca there was an option in filament profiles “activate air filtration” but its missing in Bambu studio. Im sure you can activate mode 3 though g-code but I wanted to find a better solution. I made this remix of a design I found to optimize the airflow. It is an add-on carbon filter that goes on top of the OEM one to filter all air being exhausted outside the chamber, no matter what filtering configuration the printer is in. It will filter VOCs from PLA, PETG, TPU when in mode 1, and ensure there is never unfiltered air exiting the chamber. With this dual filter setup you dont really need mode 3 anymore. Plus it ads more filtering capacity by adding more carbon to the filtration system, and splitting the air filtering work across two filters.
Do you have a photo of the bottom side? Or the exit side?
I’m thinking of turning the parts peeling fan into a recirculating filter as I think filters like this (as well as the OEM one) probably don’t have a great single-pass efficiency for VOC’s but something like this as the carbon layer is too thin and you can see through it. But adding this would help overall! I really don’t like the smell of PLA printing.
The air resistance is probably OK considering the fan is designed to work with mode 3.
My exhaust fan is currently at 30% in a cool room printing PLA. So in many situations the machine can compensate for a raised temp from more restricted airflow with increased fan speed.
A hepa filter may be effective for removing PM in this configuration,
Yeah and I guess you can just remove the restriction when printing PLA on a particularly hot day too (or get one of those newer plates that stick to PLA cooler)
Yes of course, the back plate can move up and down just fine. In regards to efficiency, will be about as efficient as the stock carbon filter in mode 3. You dont have a carbon filter packed with carbon, you need to be able to let the air pass, that why I put in that honeycomb structure. It wont be as efficient as mode 2 recirculation with ABS/ASA, but then again it does not have to work as hard with PLA/PETG. Its there to reduce VOCs, not eliminate them to 0%.
I feel like this would be far less restrictive if instead of the horizontal slats, you left it solid and then used a modifier to make that section print with infill only. 0 top & bottom layers. That’s how I’ve always printed my other filter screens.
Yes, im actually working on a refillable replacement carbon filter for the H2D with that very same design. Ill see if I can modify this auxiliary one as well, although those slats are not very restrictive.
Very nice! Looks like you’re already on top of it. Can’t wait to print these. Will this larger one also have the hepa filter? Or are you aiming for just straight up carbon for maximum voc removal?
Just carbon as I cant find a hepa that size. Also I will take apart the OEM filter after its used up to take a look, i have a feeling the hepa part is a very thin layer just for marketing and does not actually do much. I believe the H12 only filters particles PM2.5 and larger, so not the best for 3D printing anyways.
Yea, H14 would be ideal. Do you have the dimensions of the hepa filter on hand? My H2D is in the middle of a print so I can’t go measure it right now. Maybe I can see if I can find something
You could always find a suitable hepa filter that’s close to the right size and cut the material out of it to size. Slide it in place and slide the door on.
I was thinking of reusing the one from the OEM filter, as it will probably still be usable after the carbon is used up. On my bento box on X1 and P1s I had to swap the carbon way more frequently then the HEPA filters, and they were much smaller. Thats one of the reasons I wanted to take it apart as well.
Size HEPA needed is about 145mm x 170mm. Also it needs to be thin enough to allow enough space for the carbon.
Yes I had this HEPA + carbon one on my X1 and P1s in addition to the bento box and tiny built in carbon filter to triple up filtration. I thought about doing something similar on the H2D but instead I just printed the protective cover for the opening slats for now. Will need to find a bigger filter for the H2D as that one was too small to cover the exhaust.
So I got a bit impatient waiting for the no top/bottom surface and infill screen model and made it myself lol. I was able to do the 25% rectilinear infill screen instead of the slats by filling in the slats with a cube and then using modifiers. It’s printing now. I’ll let you know how it turns out.
So I finally got to install it today. Filled it up with some steam activated coconut shell carbon and it works great! I cannot smell my eSun pla+ printing anymore. We will se show long the carbon lasts.
I filled the honeycomb cells so that when it’s sitting horizontal, the cells are about 1/2 full. Don’t want to block too much airflow.
Its a good idea to swap the carbon every 90 days. Also the other carbon that is not being used, it has to be stored in an airtight container I actually store mine is vacuum filament bags. Otherwise it will absorb things from the environmental air and wont be as effective.
