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!
The right flowrate for dimensional accuracy is likely not the right flowrate to end up with solid parts where internal lines are properly smushed together. The sides of a 3D printed object aren't flat, so if you adjust the flow rate so that the bits that stick out the most are exactly where you asked the slicer to put the edges of the wall, you end up with your internal lines just barely touching each other instead of properly bonded. You want to tune your flow rate to get solid parts when you ask for them, set the line width a little wider than your nozzle to give space for material to flow outwards (which happens whether or not you want it to, but things work better if you tell the slicer it's going to happen), and then when you've got a part that really needs the dimensional accuracy to be right, maybe temporarily use Orca Slicer instead to get its precise wall feature.
So Orca got more features for this? I thought about moving over anyway.