Well here is the story:
I bought a Taz4, late last year. Pretty early on, I had an extrusion issue (filament stripping). It had turned out that a small section of the filament guide tube was accidentally pinched off and slid down inside the extruder. But, before I found that, I had assumed it was a nozzle clog. I hastily removed the nozzle when the nozzle was too hot and I damaged the threads of the nozzle and the threaded extension. Furthermore, I carbonized some plastic in the nozzle, trying to heat it up to clear the clog (forgive me, at the time I was quite new to all this).
Since then, the only change I made to the printer was a PEI bed surface (which, unfortunately seems, as I suspect, to be a little thicker in the center of the sheet than at the edges).
The recommendation I’m looking for is mainly: what to do now. Should I just break down and replace the nozzle and threaded extension?
It seems that I cannot get consistently good prints. I constantly am readjusting Slic3r settings. And am usually successful (eventually) at getting a few good quality prints. But, then all of a sudden, the quality drops severely and I have to fiddle some more. This usually results in me dropping speeds. It is now at the point that I am printing ABS at very low speed (20-60mm/s). The nozzle does not fully clog often, but I get all kinds of weird stuff happening.
I just removed my nozzle again, because I did get a clog. More carefully (as I am now) I meticulously brushed away every bit of carbonized plastic I could reach with a brush and then picked away the rest with a needle the gunk that was way down next to my .35mm hole.
However, I am still not getting great quality. My plan tonight is to go back to some Lulzbot recommended Slic3r configs and restart there, the see if I actually managed to revitalize my nozzle, and maybe the configs I was using is just now too modified to print well with the cleaned up nozzle.
So, how does this sound? Does replacing the nozzle and extension make sense? Can damaged threads really make for such unreliable prints, even after a careful cleanup inside the nozzle? I’m worried I’ll replace the nozzle and find I’m still not printing well (I couldn’t possibly go through all the quality issues I have at random).