I did some tests on my own with a dovetail. I’m using Bambu PLA basic, 0.6 nozzle, “0.3mm standard” settings, standard Bambu filament profile. The result:
Rounded corners… so you’re not alone…
After some knife action one can see the 3 walls and how they make a round corner:
I then printed a second sample with the following changes:
- no top layer so one can see the walls clearly
- set pressure advance (orca slicer) to 0.001 (wasn’t sure whether 0 would be interpreted as zero or “auto”)
- added a modifier to slow printing of inner&outer walls to 5mm/s (it looks like a separate object attached to the unmodified half, that’s a slicer bug/feature)
The result shows that PA=0.001 results in bulges at the corners (one purpose of PA is to avoid that), see red arrows. Also, there are no bulges where the speed is lowered (blue arrows), which is expected (I read that PA really only matters >20mm/s).
So I don’t know whether this helps anything except confirm the situation. It seems that you may be able to dial in the PA to improve the corners by reducing it from the standard value (dunno what that is). Unfortunately it doesn’t look like you can change PA with a modifier, so you’ll have bulging corners elsewhere in your model.
Update:
I did one more try, which is to add a little point similar to what you do:
I projected out by 0.6mm (0.3mm line width) in both X&Y. The results:
Still some roundness, but I believe this is quite a bit better than initially.
Note that you may want to dial in some elephant foot compensation on the quality tab.
Update 2:
On a hunch I reprinted the previous test with the following changes:
- outer wall speed 10mm/s
- pressure advance 0.01
- elephant foot compensation 0.2mm
I had wanted to try the outer/inner/infill order but forgot, so it’s the default inner/outer/infill…
I still got a bit of elephant foot and did a quick (insufficient) clean-up.
That looks pretty close to me. It’s not a square corner but I think if you do any sanding of the outside wall you end up removing the small bulges and it’ll come together pretty well. I’m sure it can be tuned a bit more. I can push the 3mf & step files to printables if you care.