Circular patterns have appeared on my P2S textured PEI build plate, and they won’t go away. I followed my normal cleaning routine and did not use any cleaning agents other than dish soap.
What’s strange is that these patterns only showed up on one side of the plate; the other side is completely fine. I also clean the build plate of my A1 printer using the same dish soap, and I don’t have any issues there.
Can you share a photo to help us diagnose the issue?
I’ve added photos of the affected build plate to the original post for reference.
That sure looks like something got manually applied to the plate with those back and forth but uneven swirls.
I use Bambu liquid glue on my textured PEI and see similar markings as I apply the glue with the markings showing the way I apply the glue but it dries clear and disappears as the plate heats up.
It sure looks like manual/human applied swirls though but maybe something else?
It does look like something applied to the plate, like glue stick. Seems to be down in the valleys of the texture, not on the peaks.
Try cleaning again, with dish detergent, warm water, and a nylon brush (old toothbrush or fingernail brush) or a terry washcloth.
This also looks like the movement of a sponge, cleaning cloth or other implement used during cleaning.
Did you clean with the “scouring” side of a sponge? I clean with Dawn, but rub it with my hands on both side. I don’t use a sponge. Then a clean, lint less rag to dry…
Is the name of your helper important or will any female work?
I clean it using the soft side of the sponge. I’m especially careful because I once scratched a glossy build plate, so I pay close attention to this. I use the exact same cleaning method on the back side of this plate and on my A1 printer’s build plate as well, and there are no issues with those. That’s why I can’t make sense of why only one side of this plate ended up like this.
After this happened, I even started doubting myself and wondered if I had accidentally used the rough side of the sponge. I then deliberately cleaned it with the rough side, but the pattern stayed exactly the same. I also tried heating the plate to 110°C and cleaning it several times with dish soap and isopropyl alcohol, but nothing changed 
The BBL Wiki writes “Ensure that the detergent used for cleaning the plate does not contain any oils or moisturizers, as those can be left on the plate and impact adhesion.”
As I mentioned in my previous message, this is the same detergent I regularly use to clean my other build plates. I haven’t had this issue with any of them, nor with the other side of the P2S plate. That’s why I find it unlikely that the detergent itself is the cause.
It could be enought, that someone have used your sponge for dish washing (or cleaning something oily), or the new sponge wasn‘t washed properly before first use…
Thank you for your reply. I’m not completely sure, but it’s possible that the sponge wasn’t properly cleaned before its first use, or that it may have been used for dishwashing at some point. I can’t say for certain though.
At this point, I guess there’s nothing more I can really do
It looks like dried soap residue; it’s possible that at some point you didn’t dry your tray properly.
I had one plate do something similar, although not swirls, but random spots that change color like your swirls do. I clean all my plates with Dawn dish soap using a cup brush. And I dry them with paper towels. Only one plate has had this happen, but it still works just fine. I generally wash my build plates about once a month unless I accidentally touch one.
I wash my build plates daily and print every day. I’m also not new to this — I’ve been working with 3D printers for about 8 years.
This issue appeared on only one plate and only on one side. All of my plates are cleaned using the same sponge, the same dish soap, and the same method: rinsed thoroughly with hot water, wiped with a clean paper towel, and then put back in place.
On the P2S, this problem showed up right after the first wash, while the other side of the same plate — washed at the same time, with the same materials and method — has no issues at all.
If there had been any residue on the sponge, I would expect the other side to be affected as well, but it isn’t. That’s why I find it very unlikely that the sponge or detergent is the root cause.
Hi. Try use propylalcohol for ckeaning. On cooled plate only!
From the wiki article.
The reason why we recommend detergent for cleaning the textured plate is due to its textured surface. Alcohol might just spread the oils on the print surface instead of removing it.
From AI
Bambu Lab recommends [Isopropyl Alcohol (IPA) for cleaning the printer’s carbon rods), but for the build plate, especially Textured PEI, using mild dish soap and hot water is often preferred, as overuse of IPA can potentially degrade the surface or reduce adhesion over time, though 99%+ IPA is generally safe for many materials if used with a clean cloth and for light cleaning between major washes. Always check your specific build plate’s instructions, use a microfiber cloth, and avoid contaminants like fabric softener.
