The Leads tab controls how the tool moves on and off the surface milling feature (lead in/out) and how the tool moves between toolpaths (stepovers).
Ramping
There are three choices for the Z roughing ramp style. You may plunge to depth, ramp to depth, or plunge to a predrill location.
If Ramp to depth is not selected, the tool will plunge to depth. If Ramp to depth is checked and Helical is not checked, the tool will zig-zag into the material. The angle of the zig-zag passes is controlled by Ramp angle. If Helical is checked the tool will spiral into the material. See Helical ramping for more information.
Selecting plunge to predrill location(s) will create a predrill operation(s) in the feature if appropriate (there may only be one predrill operation per feature). You must set the predrill diameter which will attempt to select a drill of that particular diameter. Be advised to select a drill smaller than (or equal to) the diameter of the tool used for the Z roughing. (A bigger tool may gouge). FeatureCAM will automatically calculate (perhaps multiple) predrill locations based upon the regions where it needs to plunge interior to the stock boundary.
The moves between toolpaths are controlled by the Stepover type.
See also Overview of surface manufacturing, surface milling feature dimensions tab, 3D Milling methods, strategy tab, Feed and Speed tab, milling tab