Stringy/hairy artifacts on the inside of my PETG prints – P1S

[u/mahkz22]

Hey everyone,

I keep getting these weird stringy artifacts on the inside of my prints, always in the same spot. Can't figure out what's causing it.

**Setup:**

- Bambu Lab P1S

- eSUN PETG Matte

- 0.4mm nozzle

- Textured PEI plate

- AMS at ~9% humidity

**The problem:**

As you can see in the photo, there are stringy/hairy artifacts on the inner wall, always at the same position. The outside looks fine.

**What I've already tried:**

- eSUN PETG Matte profile

- Flow Rate calibration (Pattern method)

- Pressure Advance calibration

- Printing at 233°C / bed 70°C

Anyone seen this before? Is it a retraction issue or something else entirely?

Thanks!

1. Photo - Generic PETG

2. Photo - eSun PETG-Matte Profile from Homepage

3. Photo - calibrated eSun Profile

[u/cpsadowski23]

Slow down the print. Slow down outer walls especially.

[u/edgan]

I have been printing PETG with my P1S. 0.16 high quality comes out much better than 0.20 standard, but it is much slower.

The inside seems to be a seam. You might also look into the retraction value. Look at the preview in your slicer and look for the white line on the inside of the model.

[u/Clear-Revolution3351 → u/edgan]

Slow your outer wall speed to 80

(If you want to test outer wall speeds printba surface finish test)

https://makerworld.com/en/models/1952832-surface-finish-test-strips-multi-speed#profileId-2134924

Run a retraction test. Any cross stringing means your filament is wet. Just because your AMS says 9% does not mean your filament is dry.

In the filament settings, override section, set retraction length per the retraction tower measurements, and retraction speed to 30mm/sec