Nozzle blobbing

After several hours of flawless printing the nozzle started blobbing. (See photo) After a short time it clogged and the extruder kept going causing a jam and a tangle around the extruder gear. I changed the filament to a better quality, same result. I changed to another filament, same result. I changed the nozzle and it began to work again with slight blobbing while starting the perimeters. I changed back to the original filament and printed the part without any issue. After printing three other parts with different filaments, the extruder jammed again. The nozzle appears to be clear. What might be going on here?

RepRap Prusa clone
Nozzle 0.4mm 180 degree F.
Bed 60 degrees F.
Hatchbox 1.75mm filament

Thank you.

What filament? Hatchbox makes many different filaments. PLA, PETG? In either case, I think your nozzle temperature is very low. I use about 210C for PLA, and 230C for PETG. There's no way your nozzle is at 180F (82C). If it's at 180C (356F) it's still way too low for either of these materials.

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rq3
What filament? Hatchbox makes many different filaments. PLA, PETG? In either case, I think your nozzle temperature is very low. I use about 210C for PLA, and 230C for PETG. There's no way your nozzle is at 180F (82C). If it's at 180C (356F) it's still way too low for either of these materials.

I've been using PLA. The temps have been working well for over a year. The problem started rather suddenly. I've ordered a new barrel in case there may be a problem there, and I've ordered a set of stepper drivers, as well.

Try cleaning any plastic from in between the teeth of the hobbed bolt on your extruder (or whatever you have gripping the filament to push it down through the extruder). Maybe you tried this, but it's the kind of thing that can slowly get worse over time.

Like you said, if you've been printing fine for over a year, then it's probably not a matter of changing settings. Unfortunately, changing settings is one of the easiest things to do, so we all jump straight to that. But it can be a lot of confusion for nothing. It's probably related to some kind of mechanical wear or buildup.

Edited 1 time(s). Last edit at 04/27/2020 11:17AM by Wissing.

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Wissing
Try cleaning any plastic from in between the teeth of the hobbed bolt on your extruder (or whatever you have gripping the filament to push it down through the extruder). Maybe you tried this, but it's the kind of thing that can slowly get worse over time.

Like you said, if you've been printing fine for over a year, then it's probably not a matter of changing settings. Unfortunately, changing settings is one of the easiest things to do, so we all jump straight to that. But it can be a lot of confusion for nothing. It's probably related to some kind of mechanical wear or buildup.

Thank you for the advice. I was able to get it repaired after a couple of weeks of trying everything. I discovered that the nozzle was pushing against the bed not allowing the filament to flow properly.