How to smooth out entry and exit of tool path "nibs"?

I am getting some great results with a compression bit in this 5 layer birch plywood.

However, the corners have these “nibs” on them and it looks like it is due to the entry and exit of the tool paths. Other corners do not have this and they look beautiful.

What might be causing this and how do I fix it?

See photos and the Carbide Create file.

Create Computer - 25.c2d (169.2 KB)

The best way to avoid this is to avoid slotting and add geometry so as to provide a roughing clearance, and cut as a pocket down to at least tab depth — then the finishing pass can plunge along the finished edge and not deflect.

Is there any other way to do this?

Perhaps I will need to compare in Fusion and see if the same problem happens. It would be most useful to get clean cuts on these corners.

Although I think I follow you on the possible solution you mentioned it seems like a lot of work to solve.

Perhaps there is an easier way!

For instance in my laser cutting CAM program you can select an “overlap length” where it will overlap the start and end cutting points so that this little “nib” does not happen.

With a compression bit one pass is best yet that is what causes this artifact.

Any other ideas?

so I assume you want to keep the frame sized middle part?

one easy hack would be to make a circle outside of the part you want to keep, but just about not touching it… right at the spot where the bit will enter for the “real” cut.
If you cut that one first (and make it say 2x the diameter of the bit) with a pocket, by the time the real toolpath starts, it can enter the wood without any force on it since you already removed most of the material in that spot.

If your using fusion here is what I do.

Go into the linking tab. Did able lead in and out and enable ramping. I use a 20 degree ramp.

Then select an entry point on a flat area not a curve.

Now when it cuts it will ramp into the wood with no lead ins. As the compression bit comes back around the amount of material and force applied is constantly reduced while cutting through the ramp area.

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