The dream of flying – at the limit of what is possible
06.07.2015 - Oliver Hagenlocher
What came first? Aluminum or the first plane? While the first plane made by the Wright brothers in 1903 still consisted of a wooden frame covered with fabric, the process of obtaining aluminum was invented 3 years earlier. The first alloy for aviation, “Duralin®” (aluminum alloyed with copper, magnesium and manganese), was developed in 1909, only 6 years after the maiden flight by the Wright brothers. Still today high-alloyed aluminum is an important part of the design of modern commercial aircraft and, at the same time, shows how closely intertwined the development of materials and the development of aviation are.
Aircraft engines – maximum strain and stress on all components
The development of aircraft engines was just as decisive for the further development of aircraft. Even though the first airplanes were equipped with propeller engines, development of jet engines began in the 1930s, initially for military applications but eventually also for civil aviation mid-century. Development of stainless steel was crucially important for the advancement of the jet engine. When it was determined that 18/8 stainless steel had a high temperature resistance, it became the first material for engines during the 2nd World War. As of 1940, nickel super-alloys began development characterized both by thermo-mechanical fatigue strength and high-temperature corrosion resistance. Added to this is the material’s excellent creep behavior, i.e. the material deformation which occurs over time as the result of loading and stressing. Nowadays it is predominantly Inconel (a trade name of the Special Metals Corporation) frequently used in engine construction.
Machining at the limits
It is very difficult to machine Inconel and other superalloys, owing to their extreme hardness. Classic technologies based on chip removal and the machine tools on which they are used are taken to their limits during machining, leading not only to very short tool service lives but also to very long machining times. EMAG, with its Precise Electro-Chemical Machining (PECM) technology, offers a real alternative for this. Unlike finish machining using chip removal technologies with their aforementioned disadvantages, PECM allows the final contour of a workpiece to be achieved without any stress on the workpiece itself or the machine and guarantees surfaces of the very highest quality, even with extremely filigree components. EMAG developed the PO 900 BF and PO 100 SF machines specifically for aircraft construction and for machining engine components offering crucial cost and time advantages during manufacture.
It is a fact that the development of the aircraft industry is closely intertwined with developments of metal alloys and machining technologies. Further developments, which will make aviation even more efficient, are waiting in the wings with new composite materials for the aircraft casing. Regardless of the path developments take, EMAG will position itself as an innovative partner to the aviation industry in future as well.