Non destructive testing, or NDT, is a method of analysis techniques used by scientists and industrial manufacturers to evaluate a product without altering or damaging the item being evaluated. Because of its non destructive nature, NDT testing is a very valuable technique for manufacturers. Non destructive testing can reduce the cost and time required for product inspections.
Non destructive testing can be divided into a variety of methods which can then be further classified into differing techniques. This makes NDT inspection useful in a wide variety of applications, but also means it’s important to choose the inspection technique most suited to your application. One such technique is industrial computerized tomography scanning, or CT scanning. We’ll discuss industrial CT scanning in this article and how it can be used in non destructive testing.
Understanding Industrial CT Scanning
In CT scanning, a computer uses X-ray technology to produce a three-dimensional image of of an object. With X-ray imaging, industrial CT scanning can capture the interior and exterior of an object. Tomography then allows you to view two-dimensional cross section images or slices of the three-dimensional object for closer inspection.
The object to be examined is placed on a turntable situated between a radiation source and imaging system. The imaging system and turntable are connected to a computer which correlates the images collected according to the position of the object. The result is a three-dimensional representation of the object which can then be further sliced into two-dimensional cross-sectional images with specialized computer technology.
CT scanning technology has rapidly improved since its invention in 1972. Years ago, to generate even a few two-dimensional slices would take hours; today an entire three-dimensional model can be generated in seconds. Today, X-ray technology can take as many as 30 frames in a single second. Modern multi-slice CT scanning systems are able to gather 4 slices of data in 350 milliseconds. They can then use the millions of data points gathered to reconstruct a 512 by 512 matrix image in less than one second.
Likewise, since its inception, CT scanning has become applicable to a wider range of object sizes. Industrial CT scanning can now be used for parts as small as 0.5 millimeters long to those as large as one meter in length and 660 millimeters in diameter. The accuracy of CT scanning equipment will vary depending on the size of the part being scanned and its density, but it typically ranges for five to 200 microns.
The speed, flexibility, and accuracy of modern CT scanning technology is what has made it applicable to a variety of industrial applications such as reverse engineering and non destructive testing.
Industrial CT Scanning as a Means of Non Destructive Testing
Non destructive testing has become one of the most significant uses of CT scanning. Computer modeling enables technicians and engineers to mathematically and scientifically evaluate a product and its components in a virtual environment.
Inspection simulation programs can rapidly model various inspection scenarios through the modification of radiography variables. The impact of these variables can then be evaluated and assessed through the CT scanning image. This enables technicians and engineers to explore a greater variety of problems. Similarly, with control of the input variables, imaging results aren’t complicated and tainted by unnecessary variables.
Before CT scanning, technicians and engineers would need to use destructive testing methods to detect any defects in a product. Internal inspections would require evaluating a two-dimensional image or turning to destructive testing. CT scanning, however, makes the characteristics of an object’s internal structure, such as its shape, density, and internal defects, readily available for inspection. With CT scanning, numerous geometric dimensioning and tolerance (GDandT) points to be analyzed at once to meet the production part approval process (PPAP) requirements.
Why Use Industrial CT Scanning in Non Destructive Testing
By enabling you to quickly detect flaws and display them in a three-dimensional image, CT scanning makes it possible to evaluate your product without deconstructing the actual object itself. As such, industrial CT scanning can greatly impact the timeline and cost of product inspection and analysis. As a means of non destructive testing, industrial CT scanning can save between 25% and 75% on inspection costs compared to other existing analysis and failure testing technology.