General CAM question regarding work piece

[radioactive]

This is probably a very stupid question but I'll ask it anyways. I'm used to drawing up an actual part in Autocad and then exporting to a CAM program. I've done some cutting with code made from CamBam and SheetCam, for example to pocket in one location, surface the top of the material, drill some holes at certain locations. However, regarding the entire work piece, in most CAM programs is there a way to input your work piece size and it will automatically generate the code to remove that unused material?

Or is this done by setting up another pocket to remove the material between the outside dimensions of your material and the piece in the center that you are making?

If this is the case, should you remove all the material or is it okay to under cut it such that the outside edge or corner just falls off once it's cut all the way thru?

[10bulls]

If I understand your question correctly, there are a couple of options.

The method I use most, is to do a 'profile' cut around the outside of your shape, down to (or nearly) the full depth of the stock.
This might be a complete outline to cut all the way around the shape, or selected edges if you wanted to just cut and shape the ends of some stock.

The first problem is that as the cut gets deeper, it will most likely clog with chips. In CamBam, you can increase the cut width (for example to 0.7" if you are using a 0.5" cutter). This will generate parallel toolpaths all the way down and open up the cut allowing chips to get out.

The other problem is what happens at full depth. It's usually a bad idea to let things fall once they've cut through. I know it is done, but you want to be fairly confident the stock will fall away and not get fouled up in the cutter.

I use holding tabs a lot to keep my 'part' attached to the stock. This also simplifies stock holding. However it does mean a bit of cleaning up where the tabs attach afterward.
Another similar approach is to machine not quite all the way through an leave a thin 'web' of material to keep the part/stock in place, but again extra cleaning up.

All this does depend a bit on the specifics of what you are trying to make and from what material.

I hope that helps.