Nikon Metrology announced on May 26, 2021 that its industrial microfocus X-ray CT inspection solutions is now enhanced with a new offset CT reconstruction algorithm to deliver better scan speed and image resolution.
When using X-ray CT (computed tomography) for non-destructive quality control of larger components like aluminum castings or battery modules for electrical vehicles, the challenge is to shorten inspection cycle times without compromising resolution. One prerequisite for achieving this is high X-ray intensity, or flux.
In Nikon Metrology’s range of X-ray CT systems, a rotating target can already triple the flux for a given focal spot size and the flux can be further increased by motorized FID (focal spot to imager distance), which brings the detector closer to the source at the push of a button.
With the release of a new offset CT reconstruction algorithm in the latest version of the manufacturer’s Inspect-X software, not only can larger components be scanned but it can also be performed at higher geometric magnification, according to the company. The Offset.CT module is available on all Nikon Metrology X-ray CT systems from 180kV through to 450kV.
With this combination of the latest Rotating.Target 2.0, adjustable FID and Offset.CT, cycle times are reduced, and better resolution is achieved.
Offset.CT scanning improves resolution when imaging small or large parts
Offset.CT is a scanning method that allows small or large components to be inspected fully while only part of the sample is within the field of view (FOV) during rotation. The component is placed such that only just over half of the object lies within the X-ray cone beam, allowing a much wider FOV and reconstruction volume.
Compared with traditional CT, this has two main benefits for component inspection. First, larger components, even those wider than the detector itself, can be scanned without having to use a larger CT machine. Secondly, it allows the component to be placed much closer to the X-ray source, allowing higher magnification and therefore significantly increased voxel resolution. Consequently, a broader range of sample sizes can be scanned at high resolution.
Advantages of source to detector distance adjustment
Adjustable FID is a standard feature in Nikon Metrology 225kV XT H systems and Large Envelope CT systems up to 450kV. The benefit of shortening the distance between the source and the detector using motorized FID functionality is that the X-ray flux is increased. It serves to improve the signal-to-noise (SNR) ratio and the image quality of digital radiographs and 3D voxel data, in addition to allowing increased scanning speed, according to the company.
Rotating the target trebles the power
Nikon Metrology's Rotating.Target 2.0 is able to generate X-rays that are three times more powerful for a given microfocus spot size, without reducing image resolution. Scan times are consequently shorter and/or denser samples can be penetrated. Rotating.Target 2.0 features a maximum voltage of 225kV and a maximum power of 450W, but for larger and denser components a microfocus 450kV rotating target X-ray source is available.