Hey guys,
Some time ago I decided to get the upgrade kit for my P1P. I also got the hardened steel nozzle and extruder gear. That’s when my trouble with printing TPU started.
I used the same roll of filament I used while I had the P1P (F3D brand, 93A). Printing with it used to be a breeze as far as TPU goes, but after the upgrade all I’m getting is mid-print clogs, which I remove as recommended on Bambu wiki (removing the filament from nozzle with a hot hex-key, then performing a cold-pull). I also disassambled and cleaned the extruder. I even managed to look into the nozzle to confirm, that there’s no residue inside.
It seems to be the nozzle’s fault, since for a test I switched the nozzle back to the stainless steel one, leaving the hardened extruder gears and the print went fine again…
I also printed with PETG and PLA+ using the hardened nozzle, seems to print well.
So, about the print conditions and what I’ve tried so far, that did not help:
230, 235, 240C nozzle, 35C bed
1 and 1.05 flow rate
Doors open/closed, with/without top glass (to mitigate heat creeping)
Retraction 0.8mm, 0.4mm, 0.1mm, then completely off
Pressure advance 0.42 (pretty high, but this is the value I got from the Orca slicer calibration), then disabled
-Filament dried for a total of 12h@55*C, in the last week, kept in vacuum-sealed bag with silica for most of the time.
-Volumetric speed: 5, then 3.6, then 3.2
-Extruder tension screw at max tightness, then loosened by 2 turns
Soo… What do you guys think? Does this warrant a support ticket to Bambu, because the nozzle is somehow faulty, or am I missing something?
You say you changed back to the previous nozzle which is a great start in troubleshooting, but did you revert your machine back to its last working state and verify that the changing results were caused by your changes? Until that diagnostic step occurs, you will be chasing too many variables.
Did you inspect the silicone sock and the thermistor on the nozzle? Sometimes filament can get wedged underneath the sock and cause misreading’s of the nozzle temp.
Although Bambu has shown deplorable responses to tickets, you might as well get in line now before the Christmas newbie rush occurs after all the boys and girls get their A1 mini from Santa and clog the support lines.
Did you take out all of the parts your changed and change them back to the original state before the problem presented itself. If you did not, how do you know which replacement component, if any, may have caused the issue?
It may also be that your filament is not as dry as you suspect or perhaps it was “overcooked” in the dryer. Does your filament as an example, still have the flex it had before you placed it in the dryer? Have you tried a different spool of TPU to rule out bad filament?
The point I’m getting at is that aside from the nozzle change-back that you stated previously, you have not chased down the variables that have the greatest impact, that being a second spool of TPU and reverting back to the original extruder. At the moment, I count three possible variable and you only chased one. Bringing the machine back into a previously known state is the first rule of troubleshooting we see folks try to skip over in diagnostics. Sure, slicer settings can help overcome a multitude of sin but in your case, you’re getting clogs. The only way that can happen is that molten material is not melting fast enough before it exits the nozzle or it is prematurely hardening inside the nozzle.
Have you also verified that the part cooling fan is functioning correctly? If it’s on, turn it off, if it’s off, turn it on.
