Ridge at cutout layer

Bambu Lab A Series Troubleshooting
1

Hi everyone,

I’m having an issue with a small ridge that appears right in the middle of my printed plate (you can see it in the photo).

The ridge shows up exactly at the layer where the internal slot begins – it’s about 1 mm high and forms around the “side walls” of that cutout. It looks like a slight offset all the way around.

I’m printing on a Bambu Lab A1 using PLA Metal, 0.4 mm nozzle, 0.12 mm layer height, and Fuzzy Skin (0.12 / 0.12).

My flow ratio is 0.97, outer wall speed 60 mm/s, wall order is inner/outer, and the seam is set to random.

I can’t really figure out what’s causing that ridge, since everything above and below looks perfect.

Any ideas or suggestions would be greatly appreciated!

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2

If it were present on only ONE side (direction of travel of nozzle) it would be probably tunable with better support, although with such a small gap you’ll need to get creative.

Present on BOTH sides of the cutout is likely a Layer Time / Shrink issue (google: benchy hull line, prepare for a rabbit hole). I’d be willing to bet one of the layers with the big flat surface that takes ages is also the same layer with the shrinkage line?

That’ll be 0.1BTC