Fusion 360 3D adaptive and thin walls

I have been trying to improve the tool paths for the BE8108 gearbox sun gear holder.  The first time, I ended up slowing things down a lot and actually took some of the initial adaptive passes in several iterations as I fixed problems, so it wasn’t clear that any one iteration would be functional from start to finish.

So,  I tried it on a fresh piece of stock, with settings that I thought would resolve the pullout issues I had seen earlier.  Lo and behold, what did I find but more pullout!  It appeared to happen in exactly the same situations as before.  The adaptive clearance would leave a thin sliver of material, then “round it off” very rapidly, resulting in a large chunk of sliver hitting the mill at once.  Increasing the minimum cutting radius and tolerance helped reduce the problems some, but didn’t get rid of them entirely.

Eventually, I managed to find this thread on the Fusion 360 forum where others were having exactly the same issue.  From there, I discovered there is an undocumented parameter, only available in the “Compare and Edit” screen called “Curve in Radius”.  By default, it is calculated based on the tool diameter, but I found that I could add a random fudge factor of approximately 1mm to whatever the calculated version was and boom, the thin slivers were handled in a much more appropriate way and the tool never rolled over them until the sharp point was gone.

I still have more bugs to work out of this toolpath, but at least that’s one down.