Getting nowhere with Prusament PETG
I am able to get some nice prints with Prusament PLA, but I am having a nightmare with Prusament PETG. First layer is always fine, but the second layer always catches on the nozzle. I thought it maybe moisture absorption in the filament, but it happens just the same with filament fresh out of a sealed packet. PETG Used to work fine when a pre-upgraded MK3S+ with the default configs. I've tried lowering nozzle temps, speeds, extrusion multiplier, but nothing seems to do the trick. I'd be grateful for any suggested that might help.
RE: Getting nowhere with Prusament PETG
After digging deeper I have found the main factor behind this issue. I had swapped out the HF nozzle for a regular nozzle, but have not switched the profile. I now can get beyond the second layer. But now I have a new problem:
When printing a rectilinear infill, I hear a large amount of 'ratcheting' as the nozzle rides across the support veins. This initially creates a very small build-up of filament on the nozzle, but at around 5mm, begins to knock off the previously extruded infill material from the print. My print is large, but has a brim and shows no obvious signs of warping or separation from the build plate.
I miss z-adjust 🙁
RE: Getting nowhere with Prusament PETG
Don't assume that Prusament PETG is dry from the factory. Mine wasn't. (Bought two rolls of it. Both were not dry.) It hissed and popped while printing, and created a mess. Yes, the package was both sealed and vacuum tight, but it was the soggiest filament I have ever experienced. (Like it was stored underwater!) Unfortunately, it was my first PETG that I had ever tried. I got help from this forum. What fixed the problem was 24 hours of drying at 55C (preferably 65C) and storing in a tight vacuum bag with over 3 ounces of desiccant. These tiny silica gel packets do practically nothing!
After that, the default settings in PrusaSlicer were pretty good for Prusament PETG.
I did find with other brand PETG filaments, that I needed to adjust the extrusion multiplier to 94% and drop the temperature to 230C for the filament after the first layer. I was getting blob build up during a print, just like you. What really fixed the problem was reducing the extrusion multiplier.
So, I recommend you dry the filament! It should cure your problems. Then and only then, reduce the extrusion multiplier, if necessary. Damp PETG does exactly what you have experienced.
If you get more serious, then consider a better dryer (with higher temperatures available). I print directly from a PrintDry unit and have no issues with soggy filament anymore.