CNC Machining in the Aerospace Industry: What You Need to Know.

The aerospace industry encompasses not only everything related to aviation and flight, but also the operation of aircraft in space, and it provides services to the private, commercial and government defense sectors. In 2019 alone, the industry contributed more than $900 billion to the U.S. economy and employed more than 2 million people, according to the Aerospace Industries Association. In 2020, however, the industry experienced the largest downturn in its history when COVID-19 affected global travel demand.

Experts agree that the aerospace industry is on the rebound, but Deloitte reports that the recovery will be different between the commercial aerospace and defense industries; travel demand is not expected to return to normal until 2024, but most governments have not cut their defense budgets and are still driving the industry. However, both sectors are expected to see some delays in planning and minor cost increases due to instability in 2020 and early 2021.

Fortunately, aerospace manufacturers are eager to meet the demands of a recovering industry. What will differentiate successful manufacturers from others is their approach to production. These companies must produce parts at top speed to make up for the past year and a half of production downtime, maximize their profit margins by eliminating manufacturing errors and wasted time, and deliver the best quality parts possible.

Why is CNC machining used in the aerospace industry?

While CNC machining is not the only manufacturing process used in aerospace, it is perhaps the most common. 3D printing is often used for lightweight components that are not critical to system functions, such as the 3D-printed polymer sensor covers for radiation monitors in the International Space System. However, for engine parts and other critical components, the required tolerances can only be achieved through CNC machining. Otherwise, the parts simply would not be precise enough to be safe. Today, CNC machining is used in all areas of the aerospace industry. For the production of screws and other long, thin parts that must meet specific tolerances, many companies use Swiss machining. For complex parts with odd geometries, such as the combustion components in modern turbines, many companies use multi-axis machining. There are combinations of 3D printing and CNC machining to bring some printed parts to tolerance. CNC machining is almost universal in aerospace, but its applications are as varied as the parts it is used to make.

What materials are used?

Aerospace was once dominated by inexpensive, lightweight aluminum. It is still used today, but composites and alloys are increasingly taking its place as the preferred manufacturing materials. Materials with lower weight and higher temperature resistance are needed for engine parts and other components that are subjected to high stresses during flight. A modern lean-burn engine can get as hot as 3,800 °F (2,100 °C) and must be made of a material that can withstand these temperatures. Heat-resistant alloys, often nickel and titanium, are becoming more common, as are nonmetallic composites such as ceramics. However, these materials are more difficult to machine than aluminum and require advanced CAM software to ensure safe machining.

5-axis machining in the aerospace industry

Aerospace parts tend to be very complex. Most have strange geometries that require difficult approaches and sophisticated workholding solutions. None of the parts can fail during use, but they are often made of fragile or difficult-to-machine materials. Many are relatively large and require machines with large work areas. The best solution to these problems is multi-axis machining, especially 5-axis machining. Every modern, competitive aerospace company uses 5-axis machining to produce parts that meet customers’ tolerance and schedule requirements.