I’m somewhat puzzled which settings I need to look at in PrusaSlicer to solve those thin slits between perimeters. I’ve dialed in the flowrate optimally for dimensional correctness and 245°C (PETG) works really well for both flow and overhangs.
At first I thought of extrusion width, but that also increases the distance between each line. Raising the flowrate closes them, but also makes the printed parts grow in each dimension outside if the intended size.
Where am I missing something? Which settings do I need to adjust to not screw up everything else?
EDIT: It’s not just corners!


It’s not only on the first layer and also not only around corners (indeed the first layer is perfectly fine). The perspective is a little bit misleading, this is the third or fourth layer. Happens on all layers, it’s just a little bit more common around corners and bends.
This comment is correct imo. Read / calibrate the pressure advance. I’ve had especially good luck with the adaptive pressure advance and highly recommend taking the time to calibrate it.
Its a little bit confusing to do, but once you get the hang of it and do a full calibration sweep it should fix all the ‘corners have gaps’ issues. (Also just any gap issues between line)
Pressure advance is going to impact any line where the head will be shortly changing directions. So though it typically is corners you can get it with any acceleration change of the print head.
Try decreasing the speed in corners and increase pressure advance a bit. There is a tuning print you can use.
It’s not just in corners.
PA can impact more than just corners. It’s when the print head is changing speed/direction
Extrusion width?