Computed tomography (CT)
Functional sequence of a computed tomography
In industrial computed tomography, objects are recorded three-dimensionally as a volume in which they are rotated 360° and thousands of images are taken.
The object to be measured is located between the X-ray tube and the detector basket. The detector captures the shadow cast by an object to be measured.
Based on the absorption values of the X-ray signals, three-dimensional sectional images can be calculated using special reconstruction software.
Cone Beam CT (Cone Beam)
The most widely used method in industrial computed tomography is cone beam CT.
Cone beam CT attempts to image the complete object on the detector by positioning the specimen between the X-ray tube and the detector.
By rotating the specimen 360°, the shadow images are captured and computed into a volume using special reconstruction software.
It is also possible to reconstruct the object at 181° which is a considerable speed advantage.
The specimen can be moved vertically and horizontally to the axis of rotation and the volume can thus be calculated from several individual scans.
Thus, even large objects can be scanned with a high resolution or large parts can be assembled on a small detector by partial scans.
Advantages:
Fast
Delivers good results
Disadvantages:
Can lead to artifact formation with multi-materials
Fan beam, lines CT (Fan Beam)
Fan beam CT is suitable for materials that are difficult to radiate through and for multi-materials.
Fan beam CT is popular for high energy scans.
Advantages:
Low artifact formation
Exact imaging of the scan
High contrast
Disadvantages:
Long scan times
Expensive
Helix CT
In helical CT, in addition to rotation in the plane, the specimen also moves in the longitudinal direction along the axis of rotation.
Which means a helical motion when viewed from the object.
Helix CT is an extension of fan beam CT.
Advantages:
Less artifact formation
Higher contrast
Disadvantages:
High amount of data
Special reconstruction software required
Planar CT, laminography, tomosynthesis
Laminography is particularly suitable for flat components such as printed circuit boards, metal sheets and all types of board materials.
This enables the smallest partial areas of large-area test specimens, such as assembled printed circuit boards, to be examined in high resolution without destroying the test specimen.
Advantages:
Scanning of partial areas possible
High-resolution detail scans possible
Scan large flat components at high resolution
Disadvantages:
Depth information limited to one area
Limited use case
Special reconstruction software required
