Grease on filament
I came in to work this morning and my Prusa MK3 was beeping. It had stopped near the end of a print and wanted me to change the filament. I have no idea why, but when I unloaded the filament, I saw that it had something that looks like black grease on it. See picture. Is this from a bearing inside the extruder?
RE: Grease on filament
That doesn't look like anything normally present in the extruder; did you add any grease yourself?
I'm betting the black caused a false filament runout on the sensor; it looks to be contamination on the filament itself (permanent marker? other black filament?)
Does it wipe off like a grease, or is it embedded?
RE: Grease on filament
We did not add any grease ourselves. It wipes off like grease. I added another photo to show you. The print finished without any more grease showing up. I will monitor it to see if it happens again.
Scott
RE: Grease on filament
Interesting. The pictures show up as links to the jpg files in the body of the message.
RE: Grease on filament
I think that is thermal degraded plastic inside the hot end. We do put some lithium grease on the Bondtech intercalation teeth, but unless you go overboard that should not get to the filament.
RE: Grease on filament
Hah. Now they're working. Perhaps the forum software takes a bit to finalize images?
I can tell that is nothing that should be coming out of your printer. I'd spend some time tracking down where exactly in the filament feed path that stuff is originating. It's going to screw up your prints, and very likely your PEI print surface adhesion if you don't get rid of it.
Do a visual inspection of your hotend and nozzle. Is there a lot of build-up there? If so, clean it away very carefully with a soft brass wire brush. Watch out for for the delicate wires. If you have a coated nozzle, use a strip of cardboard to clean it at printing temps. You don't want stuff accumulating and oozing off mid-print. Consider a silicone sock to keep the hotend tidy.
RE: Grease on filament
By the way, the end of the filament is the classic shape for a heat break jam. You might want to plan on a new non-Prusa heat break.
As for the grease? No clue ... perhaps the night shift was playing with it.
RE: Grease on filament
Here are a few possible reasons for the problem:
Extruder Gear Grease: The black substance could be from the grease used on the extruder gear to facilitate filament feeding. Sometimes, excess grease or degraded grease can end up on the filament during the printing process.
Bearing Lubrication: The issue might be related to the lubrication of bearings inside the extruder assembly. If the lubricant is leaking or has accumulated on the filament path, it could be causing the black substance.
Hotend Issues: There might be an issue with the hotend assembly, and the black substance could be related to the heating element or a component within the hotend.