I was having huge problems printing PETG up until recently on my FLSUN QQ-S Pro. My prints would fail due to poor bed adhesion, globs, strings everywhere. It wasn't until I started tweaking some lesser known settings in CURA that I was able to get it working nearly flawlessly so I wanted to share my profile to save others TONS of time.
Some of the tips I learned about PETG because it's super sticky and stringy.
Nozzle and bed temp matter a lot. I found 225C and 80C were ideal.
Retraction is a must. 6.5mm at 25mm/s
Print slower before trying to increase speed. I started at 50mm/s with 30mm/s for outer and inner walls.
Fast travel speed, 120mm/s, helps to "break" the filament off and reduce stringing.
Because of oozing of PETG you need to compensate for it by using the Retraction Extra Prime Amount setting. I set it to 0.069 which is a little more than the cubic space inside the hole of the nozzle which is 0.064 for a 0.4mm nozzle.
Max Comb Distance With No Retract is needed so that when a printing move is followed by a longer combing travel move it doesn't ooze over your print during the travel. This value is blank by default which means it will never retract the filament before a combing travel move. (bad) I set it to 25mm so it retracts if the combing travel move is more than this value.
There are some other tweaks I made to work with PETG but these were the main ones. I hope this is helpful for others!
Happy Printing!
CURA PROFILE - FLSUN QQS-PRO FOR PETG.curaprofile