3DPrinting

So, 3d prints will always have a radius on corners that is roughly equal to half the extrusion width. This is because the nozzles are circular, and the plastic comes out in a circular cross section.

From what I can tell on the picture of your part, you have a relatively wide extrusion width set up. what's the sliced width? what's the size of your nozzle?

If you want very sharp corners, you'll need to drop down to a smaller nozzle diameter to maintain other aspects of print quality- generally extrusion widths should be at least the width of the nozzle. The reason being is that your printer relies on getting good 'squish' to keep the layers adhering stronger, and the way a printer gets narrower extrusion widths is by 'stretching' the filament along, which kind of weakens things.

If you're using prusa slicer, it's a simple matter to reduce EW specifically on external perimeters and get a nice print without sacrificing too much in the way of strength, but if the difference between internal perimeters and external perimeters are too large... things may go wonky. at that point, it might be prudent to drop down to a smaller nozzle diameter. (which prints things slower.)

A minor word of warning, however. Fillets and chamfers are important aspects of design. having sharp corners looks good, sure, but putting a fillet or chamfer on an internal corner makes a stronger part.

One thing that concerns me for the inside corners along the side... Why is your slicer cutting an angle across that corner instead of making a sharp turn (see the yellow lines in the slicer image)? Most prints draw the inside lines first and the outside perimeter last, so if you have a diagonal line sitting there already then there's no possible way to force a square corner there.

Sorry for the lack of terminology, it's been awhile since I fired up my printer, but I know in Cura under the speed settings there are parameters to set how fast the head goes from zero to full speed, and if you disable this then the head doesn't have time to slow down at the corner before launching off in another direction which causes rounded outside corners like you show on the end of your print. I'm sure someone else can jog my memory about what this is called, but it would be worthwhile to check this in your Prusa settings as well.

Regardless, you're not going to get 'sharp' corners. My printer has a 0.4mm nozzle and even with decent settings and a slower speed I still get corners roughly twice that diameter, so don't expect your print to match what's drawn on the screen.

I can only add 2 things that I know of here that could help.

#1.Try a linear advance tune. That alone should give you sharper corners and more consistent details at higher print speeds.

https://marlinfw.org/docs/features/lin_advance.html

#2.A direct extruder can help with getting very precise sharp corners but from what I understand it will hurt with accuracy on curves. Also there is the whole fact that there is a motor on top of the hot end so weight and whatnot will hurt speed.

Anyway just check out #1. It should help with your issue. If not that then a feed rate tune would solve any over extrusion problems.

What printer, what slicer, what settings, what filament would help people give you assistance.

Try klipper and tuning your pressure advanced. https://www.klipper3d.org/Pressure_Advance.html

Double check your temperature, speed, and calibration.

With low quality filament I get a lot of dribble, and with high speeds it all pools up in the corners and bulges them out.

Id like to see a single wall cube print like 30x30 mm. Corners on the picture look rounded too much, but wall thickness is only 1.35 mm (right?). In ideal world you would have R0.225 on each corner so the flat part would be only 0.9 mm. Thats super small, you probably want smaller nozzle for details like that. But yeah, maybe it can be improved by tuning settings or reducing play in your XY gantry

Rounded corners like this makes me think that you have Klipper’s Resonance Compensation feature overtuned, but you’d have to really be trying to get it this bad. What printer and firmware are you using?