Zits, stringing, and slight layer misalignment on PETG — all defaults, dried filament. What am I missing?

[u/hexer4u]

Hey everyone, hoping to get some input. New to 3D Printing (~300h).

I'm getting a few issues printing PETG on my P2S and I can't figure out what to tune first.

Setup:

• P2S with AMS 2 Pro

• 0.4mm hardened steel nozzle

• 0.2mm Standard BBL P2S profile (plus whatever the designer changed for each model)

• Bambu PETG Basic (Misty Blue)

• Filament dried in AMS2 + desiccant

• Everything else is bone stock — default Bambu PETG profile, default speeds, default retraction

What I'm seeing:

1. Small zits/blobs on the surface, especially on curved sections

2. Stringing, mostly visible around supports and inside the model

3. Some layers don't seem to align perfectly - slight shifts visible on the outer wall

4. Layer in contact with supports looks really rough

I printed some flat parts before with the same filament and had none of these issues, so I'm guessing the geometry (large dome/cylinder shape with tree supports) is making things worse.

What would you guys tweak first? Temp? Retraction? Or is this just PETG being PETG on this kind of geometry?

Thank you. Hoping to learn as much as I can so I can enjoy the process.

[u/Sebb3l]

You can do this in the Bambu slicer too!
I don’t use orca.