Joining line on concentric top layer

I use concentric top layer sometimes when it works better for the part I am making but when using it before there wasn’t any joining lines because of the shape of the part.

I made a part today and wanted to use concentric because it was perfect for the functional section of the part. But the other sections have joining lines and they are more raised than I had expected.

I just want to know if this is to be expected for concentric, or are there adjustments I could make to prevent it. Here is what the joining lines look like. I can feel the bumps when I drag my finger across.

Here is what the part looks like with monotonic line top surface.

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Imho it looks like over extrusion. Did you calibrate the flow rate? It could help to reduce the “top surface flow ratio”.

I calibrated it based on a previous spool of the same brand and color. I will try calibrating it again.

I did a calibration test and it doesn’t seem to be over extrusion. The section joining lines hardly change in the over extruded samples.

All the samples had better looking joining lines than the part I printed. Maybe it is just a combination of the shape of the sections and the fact that three sections were joining together.

What does Preview show as the linetype in the “joining line” area? Is it gap filling?

I think that might be the problem. I will try it in a few days using Arachne to see if that helps, Now I understand why somebody here was complaining about gap fill before.

Arachne looks almost the same. Are there other settings to avoid gap fill?

Maybe there is no solution for this one, aside from just not filling them? It’s a bit like trying to square a circle, or in this case, squaring a triangle.

Or maybe accept the overfill but sand it down in post processing? Or vapor melt it? Or machine it?

I’m out of ideas on this one. But at least you know what the cause is now.

I think I will add a Mod to the section I want concentric, and use monotonic line for the rest.