Computed tomography methods of analysis
If the part is detected by computer tomography, a wide variety of analysis methods can be applied without destroying the test sample.
This is a considerable time advantage and cost saving compared to conventional destructive testing methods.
Methods of analysis industrial computed tomography
Data quality analysis
Monitoring the data quality of CT (computed tomography) scans based on spatial resolution, sharpness, and gray level contrast.
This ensures a reproducible and consistent database for analyses and measurement results.
The standards according to ASTM E1441 and ASTM E 1695 are supported.
Blowhole analysis / void analysis
Fault detection through non-destructive material analysis
When casting metals and injection molding plastics, air inclusions, so-called blowholes and foreign inclusions can occur.
Computed tomography enables non-destructive inspection of workpieces for voids and foreign inclusions.
Using a sophisticated AI-based algorithm, the gray values of the test specimen scanned by computed tomography are determined and a shrinkage analysis is generated from them.
- Automatic and fast detection of all inclusions and pores in the material
- Precise determination of the position, surface area and volume of each individual defect
- Determination of the geometric shape of the defect, void
- Color visualization of defects, voids and foreign inclusions in the image
- Output of a detailed report documented with pictures
- Error classification
- Definition of different tolerances, specifications by means of ROI (Region of Interest) within a component
- Assessment of the number and distribution by means of histograms
The shrinkage cavity analysis / defect analysis can be included in a wall thickness analysis.
Testing of castings for porosity by computed tomography using the P201/P202 method.
This evaluation method for porosity analysis is often used for components in the automotive industry.
Complies with Volkswagen standard VW 50093 and VW 50097.
Testing of castings for porosity by means of computed tomography in accordance with Code of Practice P203 of the Federal Association of the German Foundry Industry.
Enables 3D evaluation of critical functional areas of the sample.
Export to Q-DAS for qualification and statistical analysis of casting processes.
Nominal- actual- comparison by computed tomography
The nominal- actual- comparison by means of computed tomography offers a direct comparison to a CAD model or another solid model.
Volume datasets, CAD models and surface meshes can be compared.
As a result of the analysis, a detailed report of the specified deviations and a 3D model coded in false colors is output.
An analysis marker, which displays the exact data at the selected position, can be set at positions that are significant from the point of view of importance.
The main advantage of the nominal- actual- comparison is the fast determination of the deviation from the target without creating a measuring program.
Invisible and poorly accessible areas in the component are also taken into account without destroying it.
Particularly in the prototype stage, this leads to significantly faster development times.
- Time to Market
The duration from product development to market placement (time-to-market) can be significantly reduced.
Tool wear can be determined and analyzed during the production period by additional scans.
A tool offset can be determined from the difference of the determined data.
Wall thickness analysis with computed tomography
Wall thickness analysis with computed tomography enables the analysis of wall thicknesses on the entire component.
This means that the inaccessible areas inside the component are also analyzed without destroying it.
The component does not have to be destroyed for analysis and the actual state of the component is retained.
For comparison, the CAD model can be used and/or measured on the direct component.
For additively manufactured, 3D printed components, the analysis of wall thickness represents an enormous qualitative variable.
The wall thickness analysis can be combined with the void analysis so that the results of the shrinkage cavity analysis are included in the calculation of the wall thickness.
This represents a considerable qualitative advantage, especially for lightweight components with increasingly thin walls.
The deviation of the wall thickness can be visualized in color and a report can be issued.
The analysis can be performed using the beam method or the sphere method.
For each point of the surface, the opposite surface is searched. The resulting wall thicknesses, are the shortest distances between the surfaces.
For each voxel, the algorithm searches for the largest insphere, which can be within the surface but must include the center of the voxel.
(A voxel denotes a grid point in a three-dimensional grid. This corresponds to one pixel in a 2D image)
Coordinate metrology with computer tomography
The 3D models of a CT scan are excellent for determining functional dimensions including form and position tolerances (GD&T based on DIN EN ISO 1101). This can also reliably determine dimensions that are difficult to determine with other measuring methods because the functional surfaces are hidden or difficult to reach. In addition, the CT scan is contactless, so that deformation of the component is avoided. Therefore, measurement by CT is ideally suited for soft and ductile materials such as rubber or silicone.
When measuring on CT data, the real geometries of the functional surfaces are usually used as opposed to 2-point measurements. Thus, the real functionality can be precisely checked.
Due to the digitization of the component, extensions or adjustments to the measurement program can be made at a later date without much effort. This is possible even years after the scan was created.
Fiber composite analysis
Fiber composites are playing an increasingly important role in lightweight construction for heavily loaded components. Fiber composite material analysis by computed tomography (CT) enables non-destructive testing in this context.
Computed tomography on fiber composites for the determination of:
- Position of the fibers
- Fiber orientation
- Fiber content
- Single and multi-layer integration mesh for FEM analysis can be imported and exported. PATRAN
- Display as color-coded vectors or tensors (main stress direction) in 2D or 3D
- Color representation by means of histograms of the fiber distribution
- Line diagrams for the visualization of the orientation tensor
- Projection to plane and space
- Consideration of voids and inclusions
Control of products by means of computer tomography whether all components are present and correctly installed.
This can also be realized through the packaging.
A quick CT in a few seconds can be much more efficient here than unpacking the parts again or disassembling and reassembling them.
AI enables safe and fast decision-making in serial testing.
Disassembly can also lead to new defects, which can be avoided by checking with computed tomography (CT).