How to improve quality of overhanging curves?

This is a common problem I see with various models and all brands of filaments, but most recently I saw it with Bambu’s own Engine Model, so I figured I’d ask about it if I’m seeing with an “official” model with “official” print settings. In this post I’m referring to overhanging curves in the same layer/XY plane, not overhanging curves across layers/in the Z plane.

Here’s a photo where the two pieces on the left were printed with support (normal, snug, threshold angle of 30), and the two on the right weren’t (the left ones also were on a smooth PEI build plate while the right ones were on a textured one, but that shouldn’t be relevant):

This was on a P1S with a 0.4 nozzle with the current latest firmware and latest version of Bambu Studio. I used the Generic PLA profile for this particular print, but I observe similar results with Bambu PLA. I’m using an AMS, and this particular gray filament was only about one day old.

What I see on the right with the overhanging curved corners peeling off is common, but usually I don’t care about aesthetics and I can just cut those off and use the part just fine. However, I figured printing with support should completely fix the issue, and while while you can see the parts with support turned out significantly better, I was surprised to see there is still some minor peeling of the curved corners.

I’m wondering if there’s anything I can do to improve this print quality in general? I find this to be slightly more challenging with XY overhanging curves in the same layer (like this one) as opposed to Z overhanging curves across multiple layers, as the latter can be adjusted with the overhang speed settings for the particular curve angle, but with these XY same-layer curves there’s no particular speed setting for them.

Here’s some information about the flow, speed, and layer time for layer 3, where I observe the most peeling:

I think maybe playing with dynamic layer height would be where I would start. The other thing in question is what is your support setting? Are you bumping up to 80 or keeping it as minimal as possible? With rounded corners in the z direction , you’re going to see the most improvement when you drop your support spacing, play with the angle of your support relative to the model, and then also adjust the minimum support angle. For Bambu, a higher value means more support obviously. Since you’re asking specifically about x/y plane and not z, the support will seem less important, but it really still does play a role here along with everything else. You still have the spacing of the support as well as the spacing from the model which can both work for or against you. Just things to consider.

I believe it’s due to a combination of the chamfered edge and the filament still being soft when the nozzle comes around for the next layer. Because the nozzle is moving so fast around the small perimeter and the fan is off for the first few layers. In the filament settings tab, you can try increasing the fan speed layer time from the default 4 seconds, to say 7 seconds.