PLA fumes while printing

[robogrobo 0]

Are the fumes from the melting PLA harmful? Do I need ventilation or open an window?

Thanks for your answers.

[Daid 304]

I don't think they are. But you might want to lower the printing temperature, you get less fumes that way. Printing at 250C gives a lot of fumes, while printing at 220C gives a slight smell after a hour or so.

[joergen 2]

Are the fumes from the melting PLA harmful?

PLA doesn't make much/any fumes, and they are not harmful (AFAIK).

If you see any fumes, it is most likely water steam. The PLA is hygroscopic, and the water bubbles out during printing, causing all sorts of little surface imperfections. best to keep the PLA in sealed bags with desiccant.

[robogrobo 0]

Thank you Daid and Joergen, especially for the sealed bag hint.

[reprapfilament 0]

I don't think they are. But you might want to lower the printing temperature, you get less fumes that way. Printing at 250C gives a lot of fumes, while printing at 220C gives a slight smell after a hour or so.

I printed PLA at 185 deg, too much high temperation not good for PLA, since PLA is of bad heat stable(why? you can compare PLA with ABS, keep both on high temperation higher than 250 deg for a while, PLA wil flow out from nozzle without motor drive), when temperation up to 250 deg, it mostly go degradable(PLA is a biodegradable corn plastic),something very unknow fume emmit, and you may find the PLA filament melting flow from nozzle "dirty yellow black", I think that nothing good for health.

different supplier PLA is different process temperation, my do is 185 deg,very safe.

anyway, I don't like the smell of ABS, make me headache,must be in ventilation environment.

[rewolff 0]

FYI, from looking at the chemical formula, you can reasonably know what components end up in the fumes when it overheats.

So PLA has Oxygen, carbon and hydrogen. Most combinations of these molecules are harmless. My chemistry is probably lacking, but I'd say benzene is one of the few dangerous combinations of these. But it's really hard to make that from PLA: The three carbon molecules are spread out, while the three hydrogen molecules are connected to one carbon molecule. That won't easily make benzene.

ABS on the other hand, starts out with benzene and an N with three bonds to a carbon molecule. This could fall apart into HCN. Very poisenous. And the benzene could come loose from the hydrocarbon "tail". All in all ABS can be said to be dangerous to decompose through heating and PLA is safe.

(Pla starts out as lactic acid which you find in ... milk)