Door frame areas refer to areas in the aircraft fuselage that surround cargo doors and passenger doors. These components are important for safety, and must compensate for the structural weaknesses created as a result of openings in the aircraft fuselage.
For this reason, these frames not only need to be precisely manufactured, but also must not warp, even under heavy load. They are therefore mainly made of titanium. In order to prevent crack propagation, the titanium is beta-annealed, which significantly increases tool wear. The frames are also designed with lengths of up to 4 m and incorporate reinforcement bars, requiring high machining volumes in order to machine, without causing the component to warp. The primary focus is therefore on process reliability.