The American Society for Nondestructive Testing (ASNT), which facilitates the largest organized society for nondestructive testing professionals, currently lists fourteen viable NDT inspection methods that can be used today. One of the more recent methods available that you have probably not heard of, which falls under radiographic testing, is computed tomography, better known as CT. For most of us the familiarity to CT comes from the medical term CAT scan. Though similar in attributes, there are many differences to how computed tomography is used in industry.
In the past five years, industrial CT scanning has garnered a lot of interest within the part manufacturing industry and has become one of the more viable NDT methods used today, and for three distinct reasons: the accuracy industrial CT scanning offers, the wide variety of parts that can be inspected, and the ability to perform metrology and run various types of analysis with the scan results.
“What you’re seeing with industrial CT scanning is a nondestructive inspection method able to identify a part’s true internal characteristics, in full 3D, with the capacity to provide precise measurements. It’s the technology’s ability to qualify and validate those internal geometries and features that makes industrial CT scanning an asset to manufacturers,” says Andrew Good, lab manager at Jesse Garant Metrology Center.
Here are the four advancements that are supporting industrial CT scanning’s growing use among part manufacturers.
#1 Advancements in Image Quality
One of the contributing factors to industrial CT scanning’s growth is how the technology for digital detectors has improved. Not only have digital detectors improved in capturing better image quality, the increase in detector sizes has also allowed manufacturers who produce larger parts to use industrial CT scanning effectively as well.
#2 Advancements in CT technology have produced better NDT & Metrology Solutions
The ability to inspect internal features on a part with various complexities without the need to disassemble the part is one of the biggest contributing factors to why industrial CT scanning’s use is increasing among part manufacturers. This is evident within the aerospace industry, which has always been faced with strict part validation requirements. But now with industrial CT scanning, part manufacturers are more confident. They are drastically improving their ability to make better qualified decisions on their parts, especially during the pre-production stages of inspection. In combination to those strict requirements, the effectiveness of using industrial CT scanning for GD&T measurement plans for first article inspection reports also has contributed to an increase in industrial CT scanning’s use not only within the aerospace industry, but in automotive, medical, and consumer products as well.
In fact, NASA recently found huge success with using industrial CT scanning when it came to re-designing rocket parts using 3D printing. Before testing the 3D printed rocket injector, materials engineers at the Marshall Center performed a computer tomography scan to ensure the part was fabricated according to the design. “Rocket engines are complex, with hundreds of individual components that many suppliers typically build and assemble, so testing an engine component built with a new process helps verify that it might be an affordable way to make future rockets,” says Chris Singer, director of the Marshall Center’s Engineering Directorate.
An added value with industrial CT scanning is that one scan dataset can be used for several post processing analyses, such as inspecting for porosity/inclusions, comparisons between parts (highly effective when you are manufacturing parts at different facilities), comparisons to the CAD model, inconsistencies in wall thickness, reverse engineering, and if a part consists of carbon or glass fiber, a composite analysis can be performed to validate fiber orientation. Industrial CT scanning is also being effectively used for first article inspection during the pre-production stage of a manufacturer’s part life cycle. Finally, industrial CT can qualify internal and external measurements for PPAP and AS9102 form 3 requirements—giving automotive and aerospace engineers extensive dimensional knowledge about the internal and external features of a part.
As an end-to-end part inspection solution, industrial CT scanning has proven its worth as a practical method for inspecting parts at any stage of inspection with many analytical options to choose from. Whether validation of a part is the focus during pre-production/production, or location and measurement of defects during the failure investigation stage, industrial CT scanning can provide the support you need along every step of the way.
#3 Advancements in Software Capabilities
Despite these significant advancements in technology, in actuality, it’s the software and computing power capabilities that continue to be a huge contributing factor to industrial CT scanning's use today.
#4 The service providers
Perhaps the biggest contributing factor to the continuous increase in industrial CT scanning’s use is the service providers. It is no surprise that such an exclusive technology comes at a heavy price. A decade ago, there were very few CT systems circulating in industry for industrial applications. Currently, the purchase of a CT system along with time and cost for training and development ranges from $200,000 at a minimum and upwards into millions, depending on customization requirements. That being said, one CT system is not capable of testing every part in industry. Certain scan requirements must be taken into account in order to be able to pair the inspection project at hand with the right system. For manufacturers producing multiple parts that vary in shape and material, or for small and mid-sized businesses that only require the testing and inspection of limited applications, the investment can be overwhelming and highly unfeasible.
With the introduction of industrial CT scanning labs providing internal and external part inspection services using various systems for different applications, manufacturers have been able to develop higher quality standards for their parts. Having access to multiple CT systems at their fingertips, manufacturers are now able to verify parts accurately, and keep up with the increasing demand for high quality parts without having to invest large amounts of capital.
Undoubtedly, the accuracy, efficiency and reduced turnaround times that industrial CT scanning provides will continue its trend of becoming an instrumental tool for inspection well into the future.