3D Adaptive - Stock to Leave doesn't seem correct

[BbellYS6XC]

I am cutting some parts from plywood. Some of these parts have rabbets (rebates for our European friends). The strategy is to first use a 3D Adaptive operation to rough out the rabbets, then use 2D Contour to finish the vertical walls. Later I'll come back and cut out the parts with a profile.

The 3D Adaptive operation is set to leave Stock to Leave (STL) of 0.02" radially and 0.0" axially. From looking at the simulation and the minimum-Z on the setup sheet, it appears to actually leave 0.02" axially. If I set axial STL to 0.02", there's no change - it's the same as setting it to 0". If I set axial STL to 0.05", it actually leaves 0.06"!

The 2D Contour operation doesn't have this issue. I used the same contours in creating both operations, although the 3D Adaptive contour is closed (the horizontal surface of the rabbet) and the 2D Contour contour is just the edge where the horizontal and vertical surfaces meet.

I've attached the model having the issue. There is a single manufacturing setup and two operations. I'm primarily using the setup sheet to compare the minimum-Z values between the two operations.

Is this a bug? User error? Any workarounds?

[seth.madore · Accepted solution]

This comes down to math and your selections as well as a couple other settings.

1) You have your Bottom Height set to Model Bottom

2) You've selected contours to select the toolpath

3) Based on the Bottom Height setting of Model Bottom, the overall part height and the Max/Min Stepdown, it ends up being .02" shallow

4) Setting Bottom Height to "Selection" and selecting the face you want the tool to stop at will generate the proper offset of zero. Do note; with a tolerance of .004", it is possible that the toolpath in some areas could float around through that zone

[BbellYS6XC]

Thanks!