CT technology from WENZEL

How does industrial computed tomography work in detail?

Industrial computed tomography (CT) works like medical CT with X-rays. During the scan process, the patient, or the measurement object, is irradiated with X-rays from different angles. Two-dimensional X-ray images are recorded by a planar detector located opposite the X-ray source and stored in the memory of a computer.

The main difference between industrial CT and medical CT is that the object is rotated around the patient instead of the entire CT system. The big advantage of this is that an industrial CT system is therefore much more compact. Here, the measurement object is only placed on a turntable instead of a patient being pushed through the entire CT.

In both cases, the tomograph acts as a scanner for data collection, which digitizes the measurement object. After the CT scan, the measurement result is available in the computer's memory. The measurement result is two-dimensional images that have been assembled (reconstructed) to form a three-dimensional image stack. This stack of images can now be cut virtually in any direction using software and the sectional images can be displayed. These sectional images provide a detailed view of the interior of the measurement object.

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Do the tomographs have to be supplemented with data analysis software?

Depending on the application, specific software is used to analyze and evaluate data. Exactly which software depends on the respective application. WENZEL supports users with its in-house software. Depending on the application, the WM | PointMaster 4 CT software or the WM | Quartis software are suitable individually or in addition. In addition, the use of standard interfaces supports all common software on the market.

The focus of WENZEL's WM | PointMaster 4 CT is on CT data visualization and evaluation, while WM | Quartis focuses on the metrological evaluation of form and position tolerances during production. The special thing about WENZEL software is that every WENZEL software works with all WENZEL hardware. This enables cross-hardware automation solutions using WENZEL hardware and software. The advantages of this solution are low training costs and quick user training.

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For which applications are they most commonly used?

The use of industrial CT is very diverse. In the area of so-called non-destructive testing of materials, the task of CT is to obtain information about the internal structure of a material. Material analysis is particularly important in order to identify defects in the material of a component at an early stage before they lead to mechanical failure of the component in use. - An enormous safety gain!

Defect detection and analysis in materials is by no means the only application of CT. Once a more complex component is assembled from individual parts, further errors can occur in the interaction of the individual parts, which can be identified with CT.

However, this is far from the end of the use of CT. Special CT devices, which are designed for maximum accuracy, open up further possibilities. The task of measurement technology in the quality assurance of manufacturing companies is to evaluate the dimensional accuracy of components. Defectly produced components can thus be avoided before they are installed in more complex components. An extremely important aspect of reducing production costs.

The unique advantage of CT when used in measurement technology is that, compared to conventional measurement technology, it can capture not only the accessible surface, but also all areas inside the component. All conventional technologies used in measurement technology, such as optical or tactile scanners, cannot detect and evaluate areas inside components. In the case of geometrically complex components, or components, or transparent materials, virtually only CT scanners can be used as measurement systems.

Last but not least, such metrological CT systems in combination with other manufacturing technologies create further and new areas of application. Once the geometry of the component has been digitized in the computer's memory after a CT scan, the data can be returned to the design using special software. This process is known as “reverse engineering.”

WENZEL uses its in-house software 'WM | PointMaster 4 CT' for all applications in the area of non-destructive testing. Because of its modular structure, the software is often the most flexible solution and is also very easy to use. There are modules with a focus on CT data evaluation and visualization, as well as inclusion/void analysis. WM | PointMaster allows you to edit triangulated point clouds as well as to edit CAD data. In the measurement technology module, target is/comparison can be carried out with false color display. The same applies to wall thickness analysis or dimensions. Modules for reverse engineering CT data and compensation of shrinkage and distortion for molds in the casting sector or in additive manufacturing round off the software functionality.

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Are there sources of radiation other than X-rays for tomography?

In addition to X-rays, neutron rays or gamma rays can also be used for tomography. However, the latter are only occasionally used in industrial applications when extremely dense or very large measurement objects are involved.

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What types of objects or materials can be examined?

Industrial tomography can examine a wide range of objects and materials, including metals, plastics, ceramics, composites, and more. The size, weight and material are decisive for resolution and penetration. Components with lower densities are preferred because they can be scanned very quickly and in good quality.

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What types of defects can be detected and how does technology differentiate between them?

Tomographs can detect porosity, cracks, inhomogeneities, inclusions, and foreign bodies. The technology distinguishes defects based on their density, shape, and position in the material. The materials can be differentiated from one another by their shades of gray or brightness. Denser areas are displayed more brightly than less denser areas.

Why choose this method and not another non-destructive testing method, such as X-ray testing or ultrasonic testing?

Compared to other non-destructive testing methods such as 2D X-ray testing or ultrasonic testing, tomography offers a complete 3D representation of the measurement result with the differentiation of materials. This therefore allows complex component geometries to be inspected using coordinate measurement technology methods and software. No other non-destructive inspection method can offer that.

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Can tomographs guarantee inspection rates that are consistent with the production rates of the parts?

WENZEL CT systems can achieve high inspection rates that are compatible with production rates. In certain applications, for components with low densities, such as in the plastics sector, series/production can be measured at the same rate. The cycle time for the CT scan is in the range of a few minutes, and the cycle time per part is a few seconds. Pallet systems for customer-specific requirements in terms of part throughput are individually tailored.

The WENZEL software solution allows all WENZEL CT systems to be used during production for process monitoring. One major advantage for companies with products in the medical sector is particularly noteworthy. WENZEL supports medical device manufacturers by certifying software for process monitoring in accordance with the US FDA (“Food and Drug Administration”) regulations.

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What does WENZEL offer in this area?

WENZEL Group GmbH & Co. KG, as a long-standing manufacturer of highly accurate tactile coordinate measuring machines and fast optical scanners, offers metrologically calibratable industrial X-ray computed tomographs. This is exactly what the various WENZELS were created for eXact models developed. All EXACT models are characterized by maximum X-ray performance in the smallest space and are easy and safe to operate. Depending on requirements, a solution is used, from the eXact S desktop unit to the eXact U universal device with 300 kV.

that eXact S Table model, is an easy-to-use microfocus CT device, equipped with a long-term stable and high-resolution X-ray source. It impresses with the highest resolution of around 3.5 µm, metrological calibration capability with an accuracy, MPEE, of 6.9 µm and an impressive X-ray output of 130 kV. Without the need for secondary connections, such as water or compressed air, the device can be used wherever conventional CTs are simply too large and too heavy, for smaller measurement objects or tight spaces. Inexpensive operation with one-year maintenance intervals rounds off the advantages of the device.

In the area of medium-sized EXACT systems, the flexibly configurable models allow eXact M and eXact L, configurations for 150 kV X-ray tubes for high resolution, or 225 kV for high performance. The eXact L 150 microfocus system achieves resolutions in the range of a few micrometers approximately between 3.5 µm — 4 µm. With the eXact M 225 and the eXact L 225, the extremely high X-ray powers of up to 225kV and 1600W are impressive. The systems are complemented by a range of fast detectors up to 3k resolution.

The universal device ExCT U can be equipped with either 225 kV or 300 kV microfocus X-ray tubes. The model series can be calibrated in accordance with ISO 10360/VDI2670 and not only achieves resolutions in the lower micrometer range, but also a calibrated accuracy in the range of MPEE around 10 µm. Various high-resolution or fast 4K/3k detectors are available upon customer request. The eXact U is also available with two doors for rapid loading and unloading.

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