Re: My handmade enclosure for Prusa
Ok, Fan still able to purge air.
Right after turn fan ON - Before: PM2.5(33) PM10(37) MAX!
Right after turn fan ON - Now: PM2.5(42) PM10(55) MAX!
It seens that i get a better result with previous filter with 300g of carbon petels, not that is more effective but the true is i have added one more HEPA filter that take 20mm and that way i end to have less GAC grams inside compared to before. That may mean that HEPA filter is not what matter most with ABS, but carbon is.
I may have to remove one HEPA and fill that space with GAC and compare.
Still a difference of 10 is not that huge
Correction:
I have made a mistake reading old values, correct values are:
Right after turn fan ON - Before: PM2.5(127) PM10(157) MAX![/s]
Right after turn fan ON - Now: PM2.5(42) PM10(55) MAX!
+/-85 less particles (Right after turn fan on) compared with previous filter
So this proof GAC more effective and the extra layer of HEPA may helped to reach that number.
Re: My handmade enclosure for Prusa
New data
This time i set FAN ON fron begin and all the time, at max speed.
Notes:
I leave door open to see first layer, with door open the performance is worst because fumes escapes and there are no pressure inside the enclosure.
Here the results:
Re: My handmade enclosure for Prusa
New graph
Fan always on at middle speed (50%)
At 18:35 i put fan at max speed (100%), it start to drop util it stabilize.
This end to be a very stable solution and very effective, i'm happy with it, even 50% seens to be effective to stabilize the air inside the enclosure and good noise level. SO it's ok to run all print at 50% and wait at end to purge air before open door.
Re: My handmade enclosure for Prusa
Before i said Prusa E-ABS was way more agressive for me in terms on smell and effects, well i was right, i printed a object with that easy abs and look at particles count, also PM2.5 is maxed at 999.99 mean the sensor limit which tell us the current value is higher.
I was with fan off and my fire sensor triggers with such amount of particles, inside box looks cloudy/fog due particle count.
The dropdown was due fan start, since i can't stand a fire alarm ringing at night
EDIT: Even PM10 maxed out!
Re: My handmade enclosure for Prusa
Awesome job !!
Since you are always looking for perfection, some things to think about:
1. Centrifugal fans https://en.wikipedia.org/wiki/Centrifugal_fan are far more efficient for forced air filtering. Have you ever seen a radial fan in a home HVAC system?
2. A HEPA filter can be thought of like a screen. It has openings that don't allow particles larger than the opening to pass. Therefore, three in series will only cause triple the pressure drop and no change in the designed max particle size and some, but little change in smaller particles than the filter was designed for.
3. If used in series the first should be for the largest particle size, then smaller, then smallest. Unlike popular belief, a dirty filter cleans better, but less flow. So spreading the size allows the largest particles to not block the finest filters. The activated carbon filters should be last so they don't get clogged with particles.
4. Putting safety screens in front of your various fans really kills their performance. Rule of thumb is 1/2x diameter clearance at inlet. Get an airflow meter like this https://www.testo.com/en-US/testo-405i/p/0560-1405 and you will see.
Re: My handmade enclosure for Prusa
Awesome job !!
Since you are always looking for perfection, some things to think about:
1. Centrifugal fans https://en.wikipedia.org/wiki/Centrifugal_fan are far more efficient for forced air filtering. Have you ever seen a radial fan in a home HVAC system?
I know about that, my choise was about easy design, maxmize area, cost and noise. The bigger the fan the less static it will have, but there are monster radial fans with good amounts of static, see DELTA's, eg: PFC1212DE 35.87mmH2O, PFB1248XHE 55.23mmH2O. Noctua i'm using are only 7,63 mmH2O, thats huge difference.
I tested with only one noctua, at max speed the air still passing, but of course less effective.
So if looking for static that DELTA's are a perfect match but noise will suck, still min. static is awesome eg PFB1248XHE have 43mmH2O static.
Maybe i can find a good Centrifugal and redesign to use only one fan, eg: https://eu.mouser.com/datasheet/2/632/BCB97x94x25mm-519326.pdf
2. A HEPA filter can be thought of like a screen. It has openings that don't allow particles larger than the opening to pass. Therefore, three in series will only cause triple the pressure drop and no change in the designed max particle size and some, but little change in smaller particles than the filter was designed for.
Thats true, but HEPA height of a single filter i use is not the optimal that's why i stack them, i made the tests with one two and three, each filter i added the particle count drop alot each filter i added, so i set 3 to be optimal. The best is a DIY filter with the correct height. If the numbers were the same i would use only one.
3. If used in series the first should be for the largest particle size, then smaller, then smallest. Unlike popular belief, a dirty filter cleans better, but less flow. So spreading the size allows the largest particles to not block the finest filters. The activated carbon filters should be last so they don't get clogged with particles.
That make's sense and i tried to find that smaller filters to make better stacks and filtration but i could only find up to PM2.5 on aliexpress. If you have any please share link.
4. Putting safety screens in front of your various fans really kills their performance. Rule of thumb is 1/2x diameter clearance at inlet. Get an airflow meter like this https://www.testo.com/en-US/testo-405i/p/0560-1405 and you will see.
Didn't understand this last, you telling the fan glued to filter will kill performance and it need a space like 60mm before filter? Is that it?
Thank you for your input, keep them coming
Re: My handmade enclosure for Prusa
I know about that, my choise was about easy design, maxmize area, cost and noise. The bigger the fan the less static it will have, but there are monster radial fans with good amounts of static, see DELTA's, eg: PFC1212DE 35.87mmH2O, PFB1248XHE 55.23mmH2O. Noctua i'm using are only 7,63 mmH2O, thats huge difference.
I tested with only one noctua, at max speed the air still passing, but of course less effective.
So if looking for static that DELTA's are a perfect match but noise will suck, still min. static is awesome eg PFB1248XHE have 43mmH2O static.
Thank you for your input, keep them coming
OK 😀
I wonder what your flow rate is. Can you measure the static pressure before the first filter?
Thats true, but HEPA height of a single filter i use is not the optimal that's why i stack them, i made the tests with one two and three, each filter i added the particle count drop alot each filter i added, so i set 3 to be optimal. The best is a DIY filter with the correct height. If the numbers were the same i would use only one.
Thats interesting. It may be due to the slower flow rate with each additional filter.
That make's sense and i tried to find that smaller filters to make better stacks and filtration but i could only find up to PM2.5 on aliexpress. If you have any please share link.
Sorry, I haven't looked into this YET. The whole filter thing is a great idea !! Don't know why I never thought about it. I just avoided stinky plastics or temporarily moved the printer to the garage.
4. Putting safety screens in front of your various fans really kills their performance. Rule of thumb is 1/2x diameter clearance at inlet. Get an airflow meter like this https://www.testo.com/en-US/testo-405i/p/0560-1405 and you will see.
Didn't understand this last, you telling the fan glued to filter will kill performance and it need a space like 60mm before filter? Is that it?
Yah, this comment was more about the extruder and part fan, but would still apply. Without the testo (above) the easy way to tell is when you put the screen on and the fan speeds up because it is doing less work pumping less air.
Re: My handmade enclosure for Prusa
I dont have equipment to measure static or flow rate, but i can invent in one.
Also i have a redesign, something like that for blower 9BMB24P2G01:
RE: My handmade enclosure for Prusa
@tiago-c
Wow, this was a great thread. Reading about all your effort, designs and thought process was awesome! I am brand new to the 3D print community (haven’t even received my MK3S yet, waiting anxiously). I’ve been a little nervous about the fumes and ventilation requirements and this thread gave me a lot to consider.
any chance you have a “final” (I know final isn’t really a thing lol) design guide on your enclosure and ventilation system? Have you, per chance, shared your print files for the parts you designed?
again, this was a great thread, thank you for taking the time to post all your research!!