It's "common sense" if you're familiar enough with chemistry and biology to realize that melting plastic means some small fraction of it will 'burn' and end up in the air.
On the other hand, many entry-level 3D printers are marketed at... children, effectively. They can make for amazing christmas presents, but there's no guarantee that either parents nor child has any idea how things work at that level. There's been a concerted effort to make such knowledge unnecessary.
All of that being said, PLA fumes are about as safe as it gets. To the best of my understanding it's about on the level of cooking food. For hours, granted, and usually without a fume hood -- but I don't think it's likely to cause health issues.
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And so long as you stick to PLA or PETG, that's probably fine. Oh, and so long as your printer was built with a quality, all metal heat break, so you never get teflon fumes from scorched PTFE lining. And so long as there's never a thermal runaway that causes fire, and/or it was built with good thermal runaway protection.
These printers are still essentially industrial machinery, no matter how user friendly, and a lack of understanding their failure modes can be really bad.
> It's "common sense" if you're familiar enough with chemistry and biology to realize that melting plastic means some small fraction of it will 'burn' and end up in the air.
Last time I was near one, I could clearly smell the unpleasant burning plastic.
I know that smell, and rather annoyingly newer PLA's have somehow eliminated it. Which personally I dont see as a good thing. You used to know when someone was printing with PLA as it emitted a smell that was a mixture of a sweet popcorn and burning toast. These days they have little to no odour but I suspect its still putting out the exact same (if not worse) fumes.
Some printers also come with full enclosures and HEPA filters, which do well at removing the smell -- and no doubt some of the larger fragments -- but do not actually remove the VOCs.
A good, recirculating activated carbon filter can do that. But then you need to swap it once per week (whether or not you've been printing), and you need the right type of carbon.
On the other hand, many entry-level 3D printers are marketed at... children, effectively. They can make for amazing christmas presents, but there's no guarantee that either parents nor child has any idea how things work at that level. There's been a concerted effort to make such knowledge unnecessary.
All of that being said, PLA fumes are about as safe as it gets. To the best of my understanding it's about on the level of cooking food. For hours, granted, and usually without a fume hood -- but I don't think it's likely to cause health issues.
...
And so long as you stick to PLA or PETG, that's probably fine. Oh, and so long as your printer was built with a quality, all metal heat break, so you never get teflon fumes from scorched PTFE lining. And so long as there's never a thermal runaway that causes fire, and/or it was built with good thermal runaway protection.
These printers are still essentially industrial machinery, no matter how user friendly, and a lack of understanding their failure modes can be really bad.