Single

Only one milling pass will be made on the surface.
Illustration

Incremental Z

Down passes will be performed in Delta Z increments. You will need to specify Incr Z Above Surf / Incr Z Below Surf.
Illustration

Surface Offset

Down passes will be performed by surface offsets. You will need to specify Offset Above / Below Surf.
Illustration

Single

Only one milling pass will be made on the surface.
Plunge Mill Illustration

Multi Layer

Down passes will be performed in Delta Z increments. You will need to specify Incr Z Above / Below Surf.
Plunge Mill Illustration