white dust on extruder heat sink after printing PETG
While printing PETG, I have been noticing a gradual buildup of white dust on the extruder heat sink and walls of the enclosure. Brushes off easily. I was wondering if this was unique to my brand PETG (MatterHacker PRO series Black) or if all PETG creates this. I guess I also want to know what it is and if it might be harmful to be inhaling as it is a very fine particle.
RE: white dust on extruder heat sink after printing PETG
Found that on my heat sink too, but I don't think it has anything to do with the material.
In my case it was on the upper end of the heat sink which is well away from exposure to the filament. Additionally it was on the side of the cooling fan. Any particles released from the filament would more likely collect around the hot end and I would expect the part and cooling fans to blow them away anyway.
What I think is that it is simply dust being picked up by the cooling fan that is hitting the sink when it is hot (e.g. longer prints at higher temps). That's an uneducated guess though purely based on observation.
RE: white dust on extruder heat sink after printing PETG
Check your extruder above the heater block that it has not started to sag and is in fact touching the heated block.
Mine seemed to also produce whitish grey dust as it started to melt onto the hot end. I wonder if it is actually ash?
Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.
RE: white dust on extruder heat sink after printing PETG
In my case I found it first when I did the S upgrade. There was no sign of melting anywhere on my old MK3 extruder.
Now that you mention it, though, maybe it isn't the filament we are using, but the filament Prusa used for the parts? While there were no signs of damage to my old MK3 extruder after 4k-5k hours (maybe 20 hours of PETG), I did see similar (same?) dust on the MK3S cover fin when it started drooping on me (after 40 hours of PLA printing...). I had assumed that it was just blowing through and depositing there, but maybe it is the result of the PETG degrading from the heat of the extruder?
RE: white dust on extruder heat sink after printing PETG
The other thing it may be is chalk!.
Some filaments use chalk as an additive to increase opacity, stiffness and increase glass temperature point.
Not sure of the mechanism for the chalk to come out and am still searching for the evidence, but it could be something to do with squeezing a molten polymer which contains it, maybe it somehow migrates to the surface. Just a theory at the moment...
Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.
RE: white dust on extruder heat sink after printing PETG
I don't think it is dust getting picked up from the fan because it is coating the inside of my enclosure. I might test the chalk theory when I get home. Calcium carbonate has a distinctive orange color when flame tested.