Black blobs appear at random.

[Skangster 2]

Do i have a clog somewhere or what is this? I played around with wood fillament yesterday and i had trouble extruding it. Maybe that clogged something?

[phantom 17]

Wood filament will leave these behind if you did not clean the nozzle thoroughly, try an atomic pull a couple of times untill no black pieces are left behind

Greetz Barry

[kmanstudios 1,120]

I have found any filament that is hygroscopic will do that as it cooks the moisture out of the filament and will make a dark char over the nozzle. PVA is especially bad about this.

[geert_2 556]

Have a look at the nozzle while printing. It could also be that molten material accumulated on the outside of the nozzle, especially on small objects, or when you have a bit of overextrusion. And then that starts to burn, sinks, and gets deposited at random spots on the print.

In my experience, thick light-brown blobs usually come from the outside of the nozzle, while thin black flakes usually come from the inside, with PLA and PET. But this may be different for other materials of course.

Anyway, regularly doing an atomic pull never hurts. And you should definitely do one whenever changing filament.

Edited July 13, 2017 by Guest