Modern aircraft are normally propelled by jet engines. These engines generate propulsion by compressing ambient air in the combustion chambers and igniting it with kerosene fuel, whereupon it is powerfully accelerated through a thrust nozzle and shot out in the direction opposite of the flight path.
Both titanium materials and super alloys are used in jet engines. In the cold area, the thermal stability of the titanium alloys is sufficient, whereas for the hot area, heat-resistant materials are required. Important components include, among others, turbine housing, rings, disks, turbine blades, blisks and impellers.
Turning operations are the norm in most of the engine components. However, the milling operations that are applied in this field, e.g. simultaneous multi-axial mill turning, are of extraordinary complexity.