Anyone know what this would mean? Is it trapped air inside the filament or caused by humidity? Moisture? Or is it just nothing? Pulled it out of a hotend.
I could be wrong but that looks like moisture burn off/trapped air and the holes left from it. Did the end break off or was this from a cold pull?
I dis-assembled the nozzle and heated it up slightly with a lighter, making sure not to burn it and pulled it out.
This is a new filament supplier we are testing.
Most plastics with perhaps sole exception of PE will absorb humidity from the atmosphere. The amount of water content in plastic that is needed to make bubbles would need to be pretty high. Those are air bubbles. By the way that air could have been introduced right as plastic was fed into the extruder (Unless you own some strange vacuum chamber 3D printer)
@Whosa_whatsis any ideas?
I would say you are probably right with the air trapped. I don’t know any other reason that it would do that. Your heat zone isn’t large enough to make for a significant heat creep so I don’t see why you would have bubbling from filament sitting too long aside from in the very bottom. But even then you were saying that it jammed during a print.
Find anything in the filament? Ball bearings? I’ve printed a handful of brands that are popular in the US and really haven’t had any huge issues. That’s odd to see…
The filament may have moisture in it, when it enters the melt chamber it boils and would create pockets, but I don’t know if it would look like that.
A better determination is to extrude it and observe the extruded filament, it should be smooth.
It can also be air pockets from the initial loading, did you extrude it a bit before disassembly?
@Stephanie_A It printed fine for a few minutes, but then it jammed. I did not extrude it before disassembly. As soon as it jammed, I took it apart and used a lighter on the stainless steel heat break to soften it so it can be taken out.
Not what air/moisture bubbles look like in a cold pull, but if you used fire on it, I can imagine them re-melting into that shape.
@Whosa_whatsis so would you say it’s air/moisture? or something else possibly?
What type of filament? PLA?
On all-metal hotends I’ve had jams happen because the plug got too high and seized in the transition zone.
@Stephanie_A Yes PLA “modified for metal hotend”
Can you hear the air pockets “popping” during extrusion? I used filament that would do that. The printout quality was horrible.
@Charlie nope no popping sound. It’s been a while since I heard that.