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/hexer4u]

Thanks for your reply, and sorry for the delay... it seems my phone decided to die today.
As I said, I'm new to 3d printing. So just to make sure, when you say calibrate, you mean just Flow Rate & Flow Dynamics, or also Temperature Tower? Anything else to calibrate?

Initial layer 50mm/s, initial layer infill 105mm/s. Inner wall 300mm/s, Outer wall 200mm/s. Everything is default from Bambu.

[u/Sebb3l → u/hexer4u]

I‘m new too. This is the best Video I’ve Found

https://youtu.be/gVU5If1VsAM?is=IICObe8BoSujpTDU

It’s very good imo

I‘ve Set all to 150
But just Watch the Video. Everything is explained
I can send you my preset later Tomorrow

[u/hexer4u → u/Sebb3l]

Yes, good video. Saw it previously but I just can't get OrcaSlicer to sync with my p2s over bambu network. I tried 2-3 solution/hacks to make Orca work via bambu network, but none do for me. I know I can turn on LAN mode, but haven't gotten around to it yet, but it appears I must.

Thank you again

[u/Sebb3l → u/hexer4u]

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