PETG HF Roll Printing Issue Even After Drying

Bambu Lab X1 Series General discussions
1

Hi everyone,

I’ve been printing with Bambu Lab’s PETG HF for a while now, and it’s been fantastic — consistent results pretty much every time. I always dry the filament for about 12 hours at 65c before use (using a filament dryer), and it prints beautifully.

However, I recently opened a new roll of PETG HF and, despite following the exact same drying process (12 hours at 65°C), I noticed a dotted or pitted texture on the outer walls of my prints — as if the filament still had moisture in it.

Assuming it might need more time, I dried it for an additional 12 hours (total of 24 hours), but the issue persisted.

To rule out the printer, I tried a different roll of PETG HF on the same machine, and it printed perfectly — no texture issues at all. That tells me the issue is isolated to this one roll.

Here’s what I’ve ruled out:

Same slicer settings, same printer, same environment
Filament was stored with desiccant and sealed
Roll feeds smoothly — no tension or tangles
No visible defects on the filament strand itself

Has anyone else run into this with PETG HF? Could it be a bad batch? Over-dried maybe? Or internal moisture saturation from the factory?

Would appreciate any insight, or if this is something worth bringing to Bambu support directly.

Thanks in advance!

2

When drying do so based on weight. I take the weight before and after the drying process and then decided to continue with drying. You will need to know the weight of your spool.

ie
Polymaker - cardboard spool 140g
Bambu - Plastic low temp 207g, Plastic high temp 217g, cardbord core 37-38g

Plastic and cardboard spools hold moisture.

I’d start by calibrating the new spool.

I calibrate each color. I’ve found very different K and PA between colors.

Ironically I just finished a spool of PETG HF Dark Gray in the middle of a model loaded up another and the color is so far off that I have to start over.

1 Like