P2S PETG blobs on walls

[Enay]

Hello everyone,

I’m looking for advice on the best way to reduce/remove small blobs on the outer walls of my prints.

This issue is much more visible when printing black PETG. With other PETG colors it’s still present, but noticeably less obvious.

Setup / details:

• Printer: Bambu Lab P2S
• Filament: Sunlu PETG
• Flow Dynamics (PA ): calibrated
• Flow Rate: calibrated (Improved Flow Ratio Calibration v3)
• Print temperature: calibrated
• Layer height: 0.20 mm
• Speed: 50 / 100 / 150 mm/s (depending on the part)

I’ve already dried the filament and AMS humidity is stable ±10-12%, so I don’t think moisture is the main cause.

Question:

What settings or workflow changes would you recommend to minimize these blobs on PETG outer walls (especially with black filament)?

Any Bambu Studio tips (seam settings, wipe/retraction tuning, scarf seam, wall speed/acceleration adjustments, etc.) would be appreciated.

Thanks in advance!

[GH05TB34RD]

Were you ever able to figure this out? I’ve spent days trying to solve what appears to be the same issue you are exhibiting here.

I am running a .6 nozzle on an H2D and no amount of calibration has really solved this for me. Printing in black also, so it’s noticeable.

[Alex25]

Having the same issue. I’m not able to dry my filament anymore more. I’m also printing from a sunlu dryer. I’m on p2s using sunlu petg basic filament. I saw that turning down your outer wall acceleration may help. I saw someone turned it down from 5000 to 1000 and the blobs were basically gone but I haven’t tried it myself yet.

[Enay]

Hi, thx for suggestion about down acceleration, will try it, and share results.
Also now i have HF 0.4 nozzle, and want to check also.
Additionally i change filament settings more close to general (default), make a few prints and it was not so bad, but there are noticeable problems at the corners.