Evolution of Aerospace Materials and Advanced Machining
Nov 30, 2016Demands for airframe and exterior resiliency without sacrificing weight and fuel savings remains the holy grail of aviation. While many materials have been tried throughout the 20th Century to achieve this balance, their use is regulated by aerospace machining provider’s ability to produce them.
Early Attempts at Metal Planes
The world’s first all-metal airplane actually dates to 1915 when aviation pioneer Hugo Junkers built a tubular-framed metal fuselage covered with corrugated sheet iron. Unfortunately, while the metal surface made the aircraft stiffer and stronger, its surface roughness resulted in significant drag. Additionally, surfaces were custom-crafted for each plane, which made them slow to machine and assemble. Sheet metal skin and ribs, held together by rivets, made an appearance in the late 1920s but the usage of these materials for aircraft was still in its infancy.
Age of Aluminum
The 1930s saw the rise of aluminum aerospace machining in aircraft. At the time, the material seemed to have all the right attributes: lightweight, inexpensive, easy to machine, and it featured a modern, sleek exterior appearance. It introduced the era of the silver plane, a term still used within aviation today, often with nostalgia. At one time, nearly 70% of aircraft had skin and airframes made from this metal. Stainless steel construction came soon thereafter, followed by advanced superalloys following WWII and titanium in the early 1960s, mostly for military aircraft. At each step, aerospace machiningtechniques and processes had to evolve to keep pace with experimental new materials.
Composites Arrive
The first carbon fiber composites were introduced for aerospace materials in the 1970s. They are exceptionally lightweight, yet can be made to a tensile strength roughly five times that of steel. Composite aerospace components are used with epoxy resins and plastic to form a matrix that keeps fibers together as one-piece designs. As a result, these pre-formed components reduce the numbers of joints and heavy fasteners, which are potential weak spots. In today’s aircraft, one-piece designs are used wherever possible.
Aerospace Machining Keeps Pace
New metals and composite materials continue to be developed for lighter weight, increased strength, and for corrosion and heat resistance. At the same time, advances in aerospace machining and cutting are keeping pace with the evolution of aircraft construction. For nearly 40 years, Computer Numerical Control (CNC) machines have greatly contributed to the manufacture of a wide range of aircraft parts, sections or exterior panels. These automated aerospace machining and milling devices make components for aviation use without direct human intervention. Many large and small CNC units exist, from cutters to drills, for producing a variety of parts.
The aerospace machining industry continuously experiments with new techniques and tools to make the latest materialsfor tomorrow’s aircraft producible on a mass scale.