Lines when the router moves on the Z axis

[_Michael]

You might find this recent thread interesting as it’s about the same problem.

Vertical Grooves Left On Side Walls On Contour Toolpaths

Hi All, My LongMill MK2 cuts beautifully, but one issue I keep running into are vertical grooves left on the side walls at points where the bit enters for a contour tool path and also at the areas before and after tab locations where the bit moves up and down to continue the contour. It wouldn’t be so bad if they weren’t so difficult to sand out. Any ideas what is causing this? I’m using Fusion 360 for creating my toolpaths. Does this look like a software toolpath issue or possibly bit deflecti…