The ability of additive manufacturing to manage small volumes, create complex designs, and fabricate lightweight but strong structures makes it a natural fit for aerospace applications, where it is crucial to decrease weight. Just a small savings in weight on an aircraft can mean big savings in fuel consumption, which is good for the industry as well as the environment. That's why strong but lightweight carbon or glass fiber-reinforced materials are increasingly used in the aerospace industry; however, inspecting these materials poses a major challenge because they are geometrically complex.

Computed tomography (CT) scan of an aerospace bell crank with metrology measurements from a YXLON FF35 CT high-resolution industrial CT system.

That's where Computed Tomography (CT) comes in. CT is the latest and perhaps the most powerful development in the modern era of non-destructive testing (NDT). A CT scan produces a two-dimensional density map of a cross-sectional slice of an object's interior. A 3D volumetric model can be produced from many of these views taken at many different viewing angles that are then reconstructed using a computer. Many 2D slices can be combined by powerful software to produce a 3D image of practically any part, object, or product. This is critical for any application that requires a manufacturer to see inside an object without destroying it.

Although there are other platforms for NDT, industrial CT is most often the best solution for applications that require visualizing an object's internal features or inspecting it for defects or inclusions with high resolution. The advanced technical features in today's industrial CT systems support the operator throughout the inspection process and can help to improve productivity by eliminating issues that could potentially cause problems in post-production. This is especially important in intricate part designs for aerospace applications such as control rod ends, aircraft propeller blades, and engine turbine blades where safety is of the utmost importance.

An aerospace bracket 2D HDR (Highly Dynamic Radioscopy) scan from a YXLON MU2000 industrial X-ray system.

There are still some misconceptions about using CT in additive manufacturing (AM). It's a relatively new technique for AM, so many are still learning about how it can be used. First, there's the common perception that CT is too slow, but advances in CT scanner design and technology over the past few years have eliminated this problem. Today's scanners have come a long way to improve speed and efficacy, more than doubling their production value. Also, stringent design and production standards have resulted in system durability that withstands the rigors of high-volume use.

CT scanning resolution has also improved significantly, resulting in crystal-clear images that can detect even the most minute flaws. Many scanners can provide resolutions down to 5 to 7 microns (or less). This is quite a big step forward over past designs. Today's CT software has also gotten easier to use, with improved workflow design and advanced protocols to make reproduction faster and more accurate.

As more manufacturers are becoming aware of the benefits of the technology, CT is moving toward mainstream use for aerospace part inspection. Not only is it helping to qualify pre-production parts quickly and accurately, but CT is also finding increased usage for high-volume inspection during production stages. In all, industrial CT scanning is providing definitive and rapid results in an agile manufacturing landscape where there is no room for error.

This article was contributed by Jason Robbins, Global Segment Manager, Aerospace with YXLON, serving customers with data-driven solutions to solve complex problems and improve process control.


Tech Briefs Magazine

This article first appeared in the January, 2019 issue of Tech Briefs Magazine.

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