Industrial x-ray Computed Tomography (CT) is a non-destructive examination (NDE) technique that has been growing in application over the past several years. During a CT scan, several hundred to perhaps a few thousand radiographic images of the specimen are captured as it rotates through a designated arc, often through a full 360°. The “computed” part of computed tomography involves reconstructing those images into a three-dimensional volume that can then be interrogated in any direction, one slice—or tomograph—at a time. With the advent of micro-focus x-ray sources, those slices can now routinely be on the scale of tens of microns or less, depending on the specimen size. The advantage CT offers is its ability to provide densitometric (material and dimensional) information simultaneously regarding both internal and external features of a specimen, even if those features are on complex scales; such as is possible with additive manufacturing methods.
Nearly every part produced at CIMP-3D undergoes CT in order to ensure build quality and identify potential defects.
This CT system features a dual-tube setup, possessing both 300 kV and 180 kV microfocus x-ray tubes for penetrating our additively manufactured metal parts.
The system is well-suited for the small to medium-sized parts that the majority of contemporary additive systems are capable of manufacturing, possessing a 16” flat panel digital detector array (DDA) and a rotary stage rated for specimens weighing up to 110 pounds. Specimens of up to approximately 12” in diameter and 16” tall can be scanned in a single acquisition; specimens of up to 20” in diameter and 24” tall can be accommodated by the chamber, but may require more than one scan acquisition to capture the region(s) of interest. Analysis of the reconstructed data sets is performed with Volume Graphics VGStudio Max software, allowing not only for visual review of slices to inspect for discontinuities such as voids or inclusions, but also for advanced analysis with defect detection, nominal/actual surface comparison, wall thickness, composite fiber orientation and GD&T modules.