I built my 3D printer a couple of months ago, but I can't get it to print sharp corners. The corners in the picture should be 90°, without any fillets:
During this test print, I played with multiple parameters: speed, temperature, acceleration, junction deviation, linear advance. All of these were also individually tuned previously. Nothing seems to make a difference.
Could this be a issue with the construction of my printer? I'm beginning to think my hotend isn't rigid enough, but then I would at least expect better results at low speeds.
Edit: the printer is a CoreXY of my own design running Marlin 2.1.2.1. The Slicer is PrusaSlicer with most settings left as default (but increased speeds)
Prusa has that option too. It does perimeter last by default because that's safer when you have overhangs. It gives the external perimeter something more to stick too and not sag. In extreme cases it can even lead to printing disconnected overhangs first like the inner perimeter of a vertical screw hole which just weld to your support and make a mess.
External perimeter first does provide more detail though (specifically dimensional accuracy in the prusa help) and can avoid some artifacts so if it's safe for your part it's nice.