Boundary machining, machines along an open or closed boundary profile. A negative machining thickness can be used to machine at constant depth below the surface being machined and can be used in conjunction with cutter contact angles.

Boundary machining can be used for the machining of mould tool runner detail, or applied to engraving boundary shapes and text which can be generated using the Windows True Type^TM fonts within the NCG CAM system. The available fonts will depend on the users Windows^TM operating system.