Create a rectangle the size of your stock and the height of course to above the part.
Now:
Tool path
Surface
Rough Pocket
All
Surfaces
Set you parameters and then it will prompt you for the boundary use the rectangle at the height of your stock.
It will see the excess and come from there. Now use the Depth controls to control how deep you want it to cut.
This one of my favorite tool paths I use it all the time.
If you have troubles send me the file or attach it here and your stock size and I will break it down with levels and notes few min worth of work.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
Cadcam
Software and hardware sales, contract Programming and Consultant , Cad-Cam Instructor .