Hi folks,
I’m experimenting with printing PETG, and am really struggling with bubbles and pitting.
I dried the PETG for 8 hours, printed, got bad results, then dried it again for 12 hours in an AMS 2 Pro with the recommended PETG drying settings.
For these prints, I’m using the standard hardened 0.6 mm nozzles in a H2D.
For the non-transparent print, I used Bambu Studio’s standard settings for the PETG, nozzle, and printer. As you can see, on the surface of the print there’s lots of pits.
For transparent prints, I’ve done a number of them, following various “print like glass”-type instructions and tutorials. Basically:
- Printing slowly (20 mm/s)
- Printing hot (265° nozzle temp, although I’ve tried a wide range of temperatures within PETG’s allowable range)
- Flow rate of 1.01
- 0.2 mm layer height, 0.5mm layer width
This little print here is the best I’ve managed. It’s great except for the bubbles.
In the floor part, the bubbles are all present in the right-hand side of the photo. This is the part of the layer that gets printed first - by the time the latter half is printed (on the left), the bubbles appear to stop. In the walls, the bubbles are kinda all over the place.
I’ve never had any problems printing PLA - the printer is perfect at that. I do only use the 0.4 mm nozzles for that, and I do wonder if the printer’s struggling to keep up with the flow rate requirements of the 0.6 mm nozzles? I’ve no idea.
If anyone has any suggestions for getting rid of the bubbles, I’d appreciate it!
Hello, I would suggest printing with a 0.4 nozzle and drying the filament.
Dry it. That’s a classic symptom that the filament has absorbed moisture. The bubbles are trapped moisture expanding into steam in the hot nozzle.
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Hi Daniel,
Is that Bambu PETG? The opaque is HF, or the new Basic? Or…?
They do like to be dried, though what you describe should be plenty. One way to check is to see if it stops loosing weight. I’ve found 8 hrs is usually enough, but I let it go some more hours after the initial weighing, to make sure.
The opaque one… where are the seams on that?
For the translucent… so, if that’s BL clear, how does the filament itself look? Can you see any bubbles/spots in it? I had a clear translucent roll that was kinda junk like that, in places anyway, not consistent. Started part way through the roll actually. And the prints looked kinda similar to yours. Also it was wound terribly and kept snagging. (I have most of the other translucent colors and haven’t seen this issue with them, and they print nicely.)
FWIW, I use .6 nozzle with both those filaments quite a bit, no real issues. And with similar settings for the translucent filament, though my flow with that nozzle is set to 0.99. (1.01 for the .4 nozzle). Just automatic dynamic flow calibration, nothing custom.
Cheers,
-Max
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Thanks for the detailed reply!
Sorry, my bad. The translucent ones is the Bambu PETG Translucent Clear, and I have a Bambu Translucent Blue that behaves the same. The opaque one is from a local company called AddNorth, and in general they have high-quality filaments, although this is my first PETG from them.
The design of that model means the seam was able to be put on the inside.
Great question - they seem to be perfectly fine to my eye. I can’t see any bubbles in the clear or the blue I have, and they’re wound well. I do notice that the feeders are visibly marking the filament - you can see little ridges along it where it’s been rewound back into the AMS.
Alright, thank you for the confirmation. I’ll give them another dry — they’ve had 20 hours, but maybe they were super extra damp ¯\_(ツ)_/¯. If not, I’ll give it a go with the .4 nozzle, see if that’s better.
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