paper on VOCs/UFPs and a couple questions
Some random questions and bits of info I found while researching 3d-printing things and I thought I'd share/ask here.
1): I found this paper on 3D printing VOC's ( https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7908560/ )thought I'd share it as I thought it was pretty well done/written. (Obviously, I'm a tad concerned about microplastics and VOC's as I'm going to be putting this in my living room. turns out its not a *huge* concern)
That said, the paper shows that the VOC's are released even during the heating and cooling phases alone (albeit at a lower amount), they concluded that the release is proportional to temperature and remains significant for as long as the enclosure is at a high temp and recommended that people allow the enclosure to cool down after each print before opening their enclosure...
It also suggests that short print jobs are better, even if the same amount of material is used, generally speaking; although they didn't seem to do any work on if the nozzle starts spraying which I imagine would amplify VOC/UFP rates. (I suspect that the release is proportional to the surface area of exposed plastic that is at high temperature and weighted by each unit-area's external temperature).
(note, the paper was done using the mk2, but it was published in 21, so I think they just used a old printer---kinda curious whether the mk4's speed would mean less or more total particulates released).
The paper also talks about Ultra-fine particulates (so 100nm or less, although what counts as 'ultra-fine' seems to not actually be all that well-defined), which means that HEPA filters can't catch them (at least in general).
maybe prusa could look into getting UEPA filters on their store-front for people who are especially concerned about UFP's (either due to being "crunchy" or due to special health concerns or babies/children/elderly in the house.) My understanding is that the price has been falling in recent years for them.
2): I was told that the layer height should be <80% of the nozzle width so that the nozzle pushes the filament down as it moves over the surface. This got me thinking about the restrictions 3d printing has atm...
For those who are experienced with the fundamentals of 3d printing, would it be possible to have a tiny motorized flap oriented in the direction you are coming "from" to apply a bit of down-ward pressure, perhaps paired with a slight orientation? This being to allow for more control over the filament during the microseconds after leaving the nozzle and during initial contact with existing surfaces.
Also got me thinking about if it'd be possible to have a attachment to the head that allows the nozzle to hold the plastic in place for a brief moment from below with another surface. point being that you'd be able to (albeit very slowly) extend a bridge over gaps, or at least improve the characteristics of pushing what is possible without supports.
not sure how well the 'flaps' would *not* stick to the filament; which leads me to the question
2a): if the nozzle is actually having to press the filament down, why doesn't stuff get stuck to it? or maybe it does?
2b): If I wanna hype over improvements in 3dprinting, where can I go besides the incremental improvements prusa is doing? (they seem to be prioritizing backwards/forwards compatibility which is great but still possibly going to slow things down)
RE: paper on VOCs/UFPs and a couple questions
I've got an air quality measuring device right next to my 3D printer, enclosed in a Prusa Enclosure. In short, keeping the air filter on during prints, and perhaps even leaving the window open a crack, results in a non-detectable impact (or insignificant impact) on air quality from 3D printing. That said, my device only measures PM down to 2.5 micrometers in size.
(That said again, I think I recall reading a paper recently (don't have a source unfortunately) claiming that smaller particle sizes get trapped in air filters aimed towards larger sized particles if the air circulates several times through the filter.)
Finally, I've also noticed subjectively that something feels off when being around a 3D printer without an enclosure / air filter. I've noticed this so many times (20+ times) that I concluded it's probably not my imagination. This subjective feeling doesn't appear when printing in an enclosure + air filter.
To summarize: I feel safe printing with an enclosure + air filter + leaving a window cracked open.
PS: My advice is that it's best to try and keep one subject per forum thread!
This question comes up about once every month. If you search you will find extensive discussion. Here is a recent one on (I think) the same paper:
You will find years of recurring rehearsals - but nothing that has stopped me using two FDM printers next to my workstation.
Cheerio,
Splitting questions:
would it be possible to have a tiny motorized flap oriented in the direction you are coming "from" to apply a bit of down-ward pressure
This is already done on some large-scale concrete and clay printers used in the building industry.
2A - go look at your nozzle.
2B - Visit one of the big additive manufacturing *Industry* events/conferences, not the hobby ones, TCT rather than Comicon, or for FDM only, a RepRap event. When you see printers making human kidney microstructures from collagen, turbine parts from sintered tungeston, aerospace sections from welded aluminium wire as filament, yachts from UV laser cured gel and you go to speak to the bloke standing inside a room sized printer then realise he is just a lifesize print of the salesman grinning behind you, you discover that an XL is not the end of the line...
Cheerio,