Core One Inconsistent Z-Height across the bed
I purchased my Core One in June 2025 and it has printed flawlessly up until the past few weeks. When printing items in the center right and back of the build plate the prints go as intended. However when I print something on the front left of the build plate the print looses adhesion and peels up every time. I am printing PETG, stock nozzle, stock profiles on a clean, textured plate (no gluestick). This setup has been working well up until now.
Here are some things I've tried to fix the issue:
Cleaning the plate and inspecting for damage (none found)
Cleaning the heat bed under the plate (nothing found, plate is flat on the heat bed)
Running some of the self tests including the load cell test (no faults found).
How should I troubleshoot this next?
RE:
Do you have the same problem if you switch build plates? Is the nozzle clean? Textured plates also can cause issues when probing the bed (because they are textured). Some have found a solution by changing the z-offset.
RE: Core One Inconsistent Z-Height across the bed
Well dang if that didn't work. I didn't have another Core One sheet but I had an unused older mk3 textured sheet that was the same size and I just ran some tests off and it seems to be working like normal. I'm curious to know why a new sheet would have such a dramatic difference. I'd been using both sides of the old sheet and while there are a few spots where the PEI coating had come off they were all under a few mm.
How often should the magnetic sheet be changed?
Thanks for the help.
RE: Core One Inconsistent Z-Height across the bed
How have you cleaned the problematic build sheet? It may not be sufficient to wipe it with isopropanol (or some other solvent), since that only removes part of the oily residues and just re-distributes the rest. Washing the sheet with hot water, dishwashing detergent and a clean sponge or brush occasionally is recommended. Make sure to use "plain" detergent without added hand moisturizers etc.
RE: Core One Inconsistent Z-Height across the bed
Thanks. I went back and washed the sheet with mild detergent and water. After it was dry, if you hold it at the right angle to the light you can better see where the texture was coming off even though it's not really visible straight on.
However, I don't think that was my only problem. I've done about 10 more prints since changing sheets and you can tell that it's still not printing as it did in the past. While the majority of the prints are are staying down I can see that I'm getting lift in sharp corners and very thin bits. It's not so bad that prints fail but it's not as good as it was when the printer was new.
I've gone back and checked the nozzle again. I've been printing on the same stock nozzle since I bought the printer (+/- 40 KG of filament over 9 months) and there was some burnt residue on it. I cleaned that off with a brass wire brush but no change to the bed adhesion.
I have a spare nozzle I could swap out. Do you think that could fix it?
Conversely, is there a way to adjust how the load cell calculates the z-offset?