Same circles take radically different times to cut

I’ve had a recurring issue where two identical circles do not cut the same.

For most circles the router will cut the circle in a series of progressive steps down to the bottom. This is fast and how it should work. Unfortunately on some circles, the router will drop down make one pass of the circle, then go back up to the step over height, then drop back down for another cut and repeat until the circle is cut to the bottom. Then the router will attempt to cut the nonexistent material it just stepped over in the same up down progression. This results in the spindle needing to go back to its step-over height for two times the number of passes it takes to cut the hole. This ends up taking a ridiculous amount of time to cut a hole.

When you zoom in in easel you can see a very small step-over in the holes that take longer to cut, but I have no idea why some holes do this and others do not. I also have no idea how to prevent it. I was just living with the extra time, but my latest project had a lot of holes and the step over issue caused the whole thing to take about 5 times longer to cut than it should have. I’ve had this happen with Easel’s native circles as well as SVG files. Has anyone seen this and know how to fix it?

I have this same issue. I just spent about 3 hours correcting 28 holes (in a file that will be used many times, so worth the time to manually correct it) using bCNC. Lots of cut, paste, and move.

I think that it has to do with the way that grbl handles arcs, so how the code generator in Easel breaks them up in that way to work with it. It is one more reason why I am moving towards other code generating programs. Looking at Blender and FreeCAD initially, though also looking at EstlCAD and HeeksCAD as well. Longer term I will probably be getting V-Carve as well.