Making an extender with 2D contouring

Here's an extender for a musician's instrument. It's 85 mm in diameter. It's going to be cut out from a bigger 20 mm piece, so I only need the contouring.

I'm going to show the differences for some of the basic options for 2D contouring.

1. First select the model and click the first icon in the MadCAM toolbar to get the workpiece defined.
2. Then click the cutter icon to open the cutter library. This time a 10 mm flat cutter is selected.
3. Select 2D path->Pocketing. Then the surface edge for the hole is selected. The Contouring dialog appears.
4. Here I show the difference between Depth From Curve and Depth Absolute. When using From Curve, the cutting depth will start from the curve as zero and then go relative, I have to define the depth as -20. When using Absolute the cutting starts at Z 20 mm and ends at Z 0. The Z value will be filled in automagically when the Material Top field is double clicked.
5. I set the Step Down value to 2 mm for 2 mm cuts at a time, Skin Cut and Break Through is set to zero.
6. When everything is OK, the toolpath will be generated in a new layer.

Now the contouring is ready, but what's the difference between Skin Cut and Break Through?

1. Delete the new layer.
2. Once again go to 2D path icon->Pocketing and click on the surface edge of the hole.
3. Skin Cut, defines how much of the depth of the material that should stay. This is perfect when pieces are milled out from a sheet and they should stay with the rest of the material instead of been catapulted by the mill. Here I define 5 mm just to clearly show what happens with the toolpath, which now stops at Z 5 mm.
4. Next I go back to the 2D Contouring and define a Break Through instead. Now the toolpath is passing Z 0 mm to -5 instead. This is useful for example when a piece later will be cut of or if the bottom will be filled up with another material (like a isolating layer etc).

Ok, the hole toolpath is re-generated. I know make a Profiling for the outer edge, still 2 mm Step Down but I leave 0.1 mm Skin Cut to avoid have a loose piece when it's finally milled. The Direction (just outside the movie clip window...) is set to Outer.

Everything is tested in the Simulator.

And by the way, the musician is the stunning drummer Petter Berndalen.