Industrial computed tomography (CT) provides digital 3-D X-ray models of test subjects, thereby allowing the analysis of interior structures. Industrial CT systems typically comprise four subsystems: radiation source, manipulator, detector and PC.
Imaging begins with the capture of 2-D X-ray images, or radiographs. The test subject is rotated 360 degrees on a single axis via a motion-controlled stage, or manipulator, while being exposed to X-rays. The X-ray tube produces a conic X-ray beam that penetrates the test subject through one plane and from many different angles, sending a digital signal to a 2-D detector. The detector interprets the signal as a series of digital radiographs, producing a myriad of cross-sectional 2-D X-ray images. The 2-D images are processed in the PC with algorithms that build a 3-D rendering through a process called reconstruction.
The operator can then manipulate the 3-D model, so that the test subject can be viewed from any angle. In addition, the individual 2-D slices that make up the model can be viewed. Because image features do not overlap, CT images are said to be easier to interpret than conventional 2-D radiographic images. Accurate identification of internal feature positioning is another advantage.
In addition‚ density differences within the test subject can be identified and quantified‚ and related to desirable or undesirable features of the subject or material. And scan parameters such as cross-sectional slice thickness or data collection time can be varied to achieve the best combination of image resolution and inspection time.
Besides nondestructive testing and inspection, industrial CT has applications in materials research, reverse engineering and metrology. The technology is used to detect cracks and air voids; measure distance, area and volume; and image difficult-to-analyze areas within a test subject.
What follows are some CT product offerings available today.
North Star Imaging (www.4nsi.com) introduces efX CT software developed for the company’s CT X-ray systems. The software includes CT calibration, cone-beam reconstruction, 3-D real-time visualization and analysis tools in the same interface. The software has a five-step, start-to-finish CT interface, automatic calibration capabilities and fast GPU reconstruction speed.
The software’s scan mode option, EasyCT, is a five-step process that guides the operator through automatic calibration and the reconstruction process through an interactive interface and automatic processes.
Through the use of the software’s automatic calibration capabilities, the company has the ability to upgrade a DR X-ray system to a 3-D CT system. The DR to CT upgrade not only transforms a DR system to a CT system, it does so without all of the increased time and cost of purchasing a new CT system.
The software’s GPU-based reconstruction module includes one to four teraflops computing systems, including 240 to 960 cores for fast CT reconstruction.
Werth Inc. (www.werthinc.com) introduces the TomoScope HV Compact. The coordinate measuring machine (CMM) has tomography sensors and is suitable for measuring high-density components made of aluminum, steel, titanium, composite materials, ceramics and glass-fiber reinforced plastics.
Three stages of expansion allow adaptation to meet specific requirements: a CMM with tomography sensors; raster tomography, for measuring small features at high resolution, even on large parts; and expansion of application range through the combination of additional sensors.
The CMM has a specification for contact and length measurement deviations. Complete software integration of all functions required for automatic measurement eases use of the system.
GE Sensing & Inspection Technologies (www.geinspectiontechnologies.com) introduces the CR50P computed radiography scanner for aerospace applications requiring both high throughput and high resolution. With a laser spot size of 50 microns and high resolution afforded by IPS display screens, the scanner allows computed radiography to assume more of the duties that have conventionally been restricted to film radiography.
The scanner weighs 48.5 pounds and offers a scan resolution that can be varied from a 50- to 130-micrometer pixel pitch. Scan results can be displayed on a connected laptop or a local high-resolution monitor. The output data also can be processed using Rhythm software, which has been designed for NDT applications.
The scanner accepts flexible, phosphor imaging plates up to 14 inches wide and of virtually any length. Plates can be processed on a continuous basis, with one plate being fed into the unit while another plate is being scanned. The plates have been designed to operate in harsh environments and are scratch resistant. They are available in a sensitivity range from D7 to D4 depending on whether resolution or speed is the governing inspection factor.
Varian SIP (www.varian.com) introduces the BIR 500-450/225 CT system with high-speed distributed image reconstruction. The system includes a standard 450-kilovolt source with 225-kilovolt option as well as volume cone beam CT, helical volume CT and real-time radiographic imaging modes when equipped with a flat panel detector. High-speed distributed reconstruction is standard, providing improved image reconstruction performance on large volume data sets. Reconstruction can be run locally or over a high-speed Ethernet network. Part envelope is 500 millimeters in diameter by 500 millimeters tall weighing 30 kilograms.
Imtec (www.imtec.com) introduces the Sprite, a small foot- print CT system. Designed with ease of use and high scanning speed in mind, the system is intended to make CT practical for operators of all levels of experience.
The system uses touch screen technology and a four-stage rotary system to simplify and ensure successful scanning setup and execution.
Matsusada Precision Inc. (www.matsusada.com) introduces the 1600 X-ray inspection system, a compact unit that can be placed on a bench or desktop. It has a microfocus X-ray tube, which assures clear, high-quality images. In addition to the X-ray tube, a highly sensitive camera is incorporated within the unit, which allows the operator to capture small defects. The combination of these technologies and the company’s uRayVision software affords ease of control. Additional features, such as automatic image capturing and measurement, make the system suitable for both analysis and inspection applications.
PreXion (www.prexion3d.com) introduces ReconPro, an image reconstruction solution for industrial CT applications. The solution is hardware-based and delivers fast cone beam CT reconstruction. It consists of PX-230AX reconstruction boards (PCI format) that employ the company’s XTrillion 3.0 processors, which use CBR software with Feldkamp algorithm. The solution is configurable, responding to custom requests such as limited angle CT (cone beam angles less than 360 degrees) or planar CT (for scanning flat and large objects). Multiboard configurations of ReocnPro provide faster processing of large volume data.
Metris (www.us.metris.com) introduces the XT 225 H with a rotational target source that increases overall CT scanning performance. By establishing up to five times more X-ray flux, operators can either speed up data acquisition by a similar factor or increase data accuracy by taking more radiographs in the same time.
Traditional X-ray sources using fixed targets can only receive a limited flux of electrons to avoid damaging the target. By introducing a rotating reflection target that yields much better cooling performance, the electron flux on the rotating target radically increases without the risk of permanent damage. This boosts X-ray flux by a large factor and enables operators to obtain faster CT data acquisition or achieve higher CT data accuracy in the same time span. The rotating target is available factory fit or field retrofit.