I'm printing with PLA on a "PEO" print bed (really a textured PEI), on my heavily modified ender 3, and there's a pattern on the bottom of my first layer that I'm trying to get rid of. The top of the first layer looks fine, and changing the z offset in either direction doesn't help. I've also tried slowing down the print speed because I thought the extruder might be skipping, but I'm still seeing it at 10mm/s. Any idea what could be causing it, and how to get rid of it?
Pic: https://sh.itjust.works/pictrs/image/31cd6cef-16de-47b3-995f-197f7d0b432d.jpeg
Edit: the first layer went down from the bottom left to the top right, but the pattern I'm seeing is perpendicular to the extruder path
It's hot - 60 bed, 220 nozzle. I'll try 40/200
40/200 looks the same as 60/220. I can try 60/210 but I don't think it will be any different.
I tried printing a disk with the bed at 70c and it looks better. Going to try with it even higher. This sheet has a +0.350 z offset compared to my normal PEI sheet, so that might contribute to low heat conduction.
For PETG that's not that hot. On my i3 clone I was usually 70 bed and 230-235 nozzle. I would try a temp tower and do what looks best. Based on what you've said so far, temp does seem like a possible culprit.
This is PLA, I can't get PETG to stick to the "PEO" bed plate.
Ah, sorry. That does sound a bit hot for PLA. I still suggest a temp tower. If you're having bed adhesion issues, have you cleaned your bed with dish soap lately? Be sure to use only paper towel to clean/dry it - not a sponge or towel. If that's impractical, I've found Windex to work better than IPA.