I really struggled yesterday with printing PETG with a 0.2 nozzle on my A1 mini.
To get it to work nicely I had to:
- Switch from smooth to textured plate
- Up bed temp from 70 to 80 (measuring the bed temp with an IR gun showed the bed temp to consistently be 10deg below the target temp)
- Up nozzle temp from 255 to 265
- Slow speeds down by 2/3rds and halve volumetric flow
- Slow accelerations down to 1/10th
All worked very well in the end. I did the changes in three steps (plate/temps/speeds) and all got incrementally better. Ended up in a very nice part.
First failure was bed adhesion, second was lots of stringing and poor layer adhesion, third was vertical spikes where each deposit started that then picked up on the next pass.