Blobs on first layers on first prints  

Blobs on first layers on first prints

Hi,

I've noticed few times lots of blobs in the first printed layer when printing with PETG. Strangely, after longer prints they do disappear. I believe all times I've noticed them it was after switching from PLA to PETG and obviously after a fair amount of time. In some case PETG filament was simply hanging on second filament arm, though I also believe I had it in a closed bag in some other cases.

Note, 1st layer is already removed from build plate.

I've also noticed that after printing for a while (8h print) next print does not have such issues. The only conclusion I could make that it might be moisture issue, though I would like to verify it or find real reason. I got some suggestions that surface is not clean - but I did put my usual isopropyl alcohol amount and wiped it before the print. First level leveling potentially is also an issue, though that does not explain why it is not constant issue.

• Printer: Prusa mk3s, firmware 3.9.3
• Fillament: Prusament PETG Orange
• Nozzle 0.4mm
• PrusaSlicer 2.3, Standart Prusament PETG profile, 0.20mm Quality 

Thanks!