Quick question for the pros: what exactly ist the residue that appears on the glass after printing appx. 150hrs?
I am aware that this is some compound resulting from heating the filament - is anyone aware what it is in terms of constituents?
I am printing 90%petg hf…
This is most likely caused by emissions released from the filament as it is melted and extruded through the nozzle. ASA and ABS are well known for producing more residue and deposits, but all filaments release some level of emissions to varying degrees, including VOCs and ultrafine particles.
Yup.. people who run non enclosed printers in their living- or bedrooms, are breathing that stuff. The enclosed printers leak some too. Get an air purifier and place it near the printer, the filters are quite good in capturing micro and nano particles, thanks to brownian motion.
I do not mind too much about air quality as the printer sits in the basement…is anybody aware of any toxicity of the residue -obviously quite concentrated - to touch (or licking the glass door 
) ?
You are kind of doing a distillation of whatever it is. It’s concentrating on all the cool surfaces in the printer but just visible like that on the glass but it’s likely everywhere in there.
On toxicity it’s hard to say. Filament has colorants with their own stuff in them, and maybe plasticizers, and maybe even unreacted monomers in there. Plasticizers and unreacted monomers can be dangerous but no idea how dangerous without knowing what the residue is. Unreacted monomers can be very dangerous. And no idea how much - if any - of this stuff is in that haze.
If you have a university with a good chemistry department nearby, you can take a new single-edge razor blade and scrape it off the glass into a clean/dry lidded glass jar, or just unmount and take the door with you being careful not to disturb that layer or contaminate it. They may or may not analyze it for you for free. Take some of the filament you print with too.
May just depend on how you approach them. If you go prepared to explain how lots of people use these filaments and breathe the fumes, they might see a publication in it and grad students need and want opportunities for publications.
You’ll want to approach an analytical chemistry group or possibly an organic chemistry group but analytical will likely have the proper equipment to analyze it. Probably either LC/MS or GC/MS (liquid cromatography/mass spectrometry or gas chromatography/mass spectrometry. The chromatography front end separates out components of mixtures and the mass spectrometer identifies what each bit is. GC/FTIR (Fourier transform infrared spectrometry) would also be a candidate. Go armed with the extruder temperature you use since it will give them an idea what temperature range they are looking at for the GC analyses. The MS/FTIR instruments frequently have libraries of chemicals they can compare with to identify what the components are.
If you do hit up a local university and someone bites, be sure to take them out to lunch or buy them a beer. You might even end up with credit in a scientific paper. 
Bambu petg-hf produces a lot of dirt and fine string. I am not saying that other brands don’t.
It is special coating to plastisize your lungs from the insdie.
I mostly print PLA and a little TPU. I was cleaning my glass door on the X1C about twice a month when I was busy. At first I thought it was dust but it’s a greasy feeling substance that smears. It cleans easy enough though. I use Purity Lens Cleaner. I can only imagine what the top glass is like. I have one of the AMS units on top of it so it never gets cleaned. I’m assuming the inside walls and plastic get the same coating but I’ve never checked.
Edit: I also do the camera lens.
Crazy - I had open printers for more than 10 years and never wasted a thought on that.
I might get this analyzed - coincidentally, I know the right guy.
Thank you for your input & explanation!
Print almost exclusively with ABS and need to clean the glass once a month or so
If you do, please report back. Would be very interesting to know.
Here they ran a project to investigate what a 3D printer emits into the air.
My colleague’s wife led that project.
In principle, almost all filaments emit substances that may be harmful to health, especially if the printer is used in a poorly ventilated area.
So regardless of what material you print with, the filters should be kept in top condition, and the room where the printer is located should be well ventilated.
PETG-HF does this to mine pretty fast. Of course ABS/ASA do as well, but as far as I am concerned negative pressure on the printer ventilating outside is my personal practice. I’ve seen the debilitating effects and had to care for family members suffering from COPD due to working in environments with harmful VOCs
Bambu’s PETG-HF seems to release a lot of PM (particulate matter). My in chamber air scrubber filters were discolored quite a bit after just one spool of it and my windows looked like yours too. A PM meter placed just to the left of the printer confirmed it during purging. One of the reasons I stopped using PETG-HF. It’s nearly as bad as ABS, just without the styrene.
I was thinking its hand prints. I will have to start wiping it down more often. I wonder what it tastes like?
I print almost exclusively ABS and some ASA for parts. The inside of my X1C looks like this, just clean it up and keep going.
Agreed, I find that Windex works pretty good to clean off this residue.
Again, my worry was not the process of cleaning. It was rather the question what I am breathing…I had open printers before and it was not clear to me how much pollution these are doing with non technical filaments.
I guess I look into ventilation out of the window.
There have been some discussions about air quality meters here and their responses near operating printers. They don’t tell you what they are responding to in particular but they do respond to hydrocarbons in general and can show significant concentrations.
There are some “electronic nose” sensors out there but they need to be calibrated against what they are sensing to get best results.
A general air quality meter is inexpensive and can at least warn of significant concentrations of “something”.
The residue is a thin film of condensed byproducts from heated PETG filament.
It mainly consists of PETG oligomers (short polymer fragments) that become sticky when they cool.
You also get condensed VOCs like acetaldehyde and glycol derivatives released during extrusion.
High-flow (HF) additives contribute additional volatile compounds, increasing buildup.
These vapors condense on the cooler glass inside the enclosure over time.
