Hi,
I have been using PETG in dark gray for about six months now, and it has always produced very clean and high-quality prints. Today, the spool finally ran out, so I opened a new one. The package was still factory-sealed and vacuumed.
After installing the new filament, I immediately noticed a very rough and uneven surface on my prints. Can anyone explain why this might be happening?
All of my filament is stored in a closed cabinet, in the dark. After opening, every spool is kept in a zip-lock bag with desiccant packs. Up to now, I have never had any issues. I currently have around 40 kg of filament at home and have printed well over 100 kg in total.
As shown in the attached image, the lower part of the print was made with the old filament and has an excellent surface quality, while the upper part was printed with the new filament and shows the rough surface.
Any ideas what could be causing this?
Thanks
Moisture.
Does not mean that the filament is dry.
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Wow, I have honestly never experienced this before. Even filament that has been lying open in my office for months has never caused issues like this. I have never had any problems with moisture so far.
I need to check again, but I believe I bought this filament in October or November 2025. In that case, Bambu Lab should take this defective filament back. The filament is new and was still vacuum-sealed.
I am not willing to buy a filament dryer just to dry brand-new filament. I simply don’t see the point in drying new filament right after opening it.
Does it say anywhere on the packaging that the filament is guaranteed to be dry?
If you want consistent print quality the only way to do this is to ensure that the filament is dry and the only way to do this is to dry your filament.
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Just a heads up: You’ll be told what to look out for before you buy. Some filament is less sensitive to humidity than others; the one you picked is one of the more sensitive types:
Of course, drying filament isn’t the solution to everything. However, I would describe this as a “reading error” rather than an mistake on Bambu’s part. You will also find this information provided by other manufacturers, depending on which filament you choose.
If you had specified the exact P-series model, we might have been able to tell you whether it can be used to dry filament. However, you can also read about it here:
