filament bubbling? Rostock max v2, standard hotend with 1x 40w heater

[n108bg]

So i have a rostock max v2. I managed to blow out both of the resistors a month or so ago, so i upgraded to a single 40w ceramic heater. Well, since then, i have been running into quality issues, specifically all of the filament i use bubbles. TPU is the worst, i've noticed at 12mm/s, quality is ok, but a little bubbly in spots. If it prints out a thin section, it bubbles a lot. I've been running typically on the low end of temps, 210 on TPU, 230 on Esun PETG, and every time, i run into some form of bubbling. any help?

[Tincho85]

have you tried drying your filament?

[n108bg]

yes. Some filament is even pulled from packaging

[Tincho85]

A lot of people here and myself included use that heater cartridge, so I don't think that would be the issue.
Maybe it's being over cooked? Check the temperature with a thermocouple if you can.
Also, if you haven't already, try with filament from a different supplier.

Best of luck.

[n108bg]

I was on the reprap forum, they were thinking it could be an airleak between the peek and metal bits, so i'll probably just print a holder and swap for a v6.

[Ail]

Did you do the pid tune again with the new heater? Replace thermistor as well? If you don't have another way to confirm temps I would use some pla, warm up to ~160 and manually try to push some filament through. if it comes out easy your temp readings are probably off. (Make sure the thermistor didn't get loose etc when you were changing things around) you can use any filament, just set the temp below a known working temp and make sure it's not coming out when it shouldn't be. If your temps seem to be fine make sure your nozzle is tight etc. so you know air isn't getting in some where.

[n108bg]

Did PID tune, did not replace, but did re-insert thermistor. I'll take a look and see if that's the case.