MK3S+ PET/G, XT oozing  

MK3S+ PET/G, XT oozing

Not exactly first print issue, this was a problem since I first assembled the new MK3S kit.

Basically, when the bead is heating and nozzle is already at 230, PETG filaments ooze a little bit (maybe about 1cm total). I have to manually remove the ooze with pliers just before the print starts so it won't run the first layer. However even with this problem I was getting good results with PETG - I rarely switched to PLA.

This problem for some reason does not exist with PLA filaments.

Recently I swapped the nozzle to Hardened one to print XT-CF20 filament, and the problem became worse with this filament. Basically every attempt  failed at around 10-20 minutes with huge glob of ooze dropped somewhere in the middle of print.

So the problem I noticed while swapping the nozzle is that the initial kit assembly was very wrong- the nozzle completely screws into the head, which means that there is a gap inside the heated part which may be filled with filament which explains the oozing since this buffer could contain the excess filament that is oozing - this was confirmed by the fact that XT-CF20 filament oozed by about 5 cm when left heated for long time. This probably also caused retraction problems (since retraction borrowed filament from the buffer rather than actually retracted) which caused the glob of goo ruining prints.

So I performed the E axis mk3s+ upgrade, during which I also fixed the incorrect nozzle placement by screwing the heated part farther so nozzle would fill the gap. I hoped this would solve PETG oozing as well.

However it's still oozing. But it certainly helped - my XT-CF20 print finished almost without issues the first time after upgrade (there were still some issues in the middle of print with some pieces of filament sticking out and touching the PINDA but it didn't ruin the print).

Anyway, my question is, does everyone have this PETG oosing issue or I still have some defect that's causing this? Maybe my print head assembly needs replacement because it's too clogged to be cleaned up by now since it was incorectly used since start? I cleaned up a lot of filament between heatsink and heated part by the way so it was escaping the filament path all this time. Maybe it's damaged somehow?