![]() Since PCI setups are easier and faster to create with fewer parameter for the inspector to configure, the technique enables better consistency between inspections and different inspectors. More Consistent Results and Easier Sizing By using the peak of the tip diffraction response from the notch, the defect height can be measured with the cursors.Ĥ. The sizing accuracy of a PCI setup can still be validated, but with a notch sample. Gain readjustment between scans based on the types of reflectors found is also no longer necessary, reducing the need to repeat TFM scans to make sure that the data is valid. With the need for gain adjustment eliminated, the time and effort required to create a setup that provides a high-quality image is greatly reduced. When you select “Phase Coherence” mode in the OmniScan X3 64 setup parameters, you’ll see that the gain adjustment is blocked since the amplitude is not considered for the final PCI data. This means that the setup step where you use a known reflector in a calibration block to adjust the gain is rendered unnecessary. PCI is a technique that is entirely amplitude free. No Need to Preadjust the Gain to a Known Reflector ![]() After the wave sets are chosen and the voltage is set to 160 Vpp (voltage peak-to-peak), everything is good to go.ģ. This makes preparing for an inspection easier and faster since the scan quality is less sensitive to the configuration. Even if the signal of the elementary A-scans is saturated, this will have no impact on the final PCI data because only the phase information is considered and accessible. Since PCI is based off the coherence of statistical variance in the phase of each elementary A-scan, the coherence level between all A-scans cannot exceed 100%. This can be due to their size, type, or orientation compared to a side-drilled hole (SDH) in a calibration block or another known reflector. Despite calibrations and gain adjustments during the setup, it is still possible that certain reflectors saturate the signal. One of the challenges with amplitude-based techniques is signal saturation. And, since PCI on the OmniScan X3 64 flaw detector generates a live image, it doesn’t require the full raw data for post-acquisition processing.Ģ. This makes the analysis easier as it removes the need to scan at multiple index points. The final image using the PCI mode is also completely independent of amplitude. Because the TFM acquires the volumetric data, the defects can be located and sized in all directions. PCI is a powerful technique for identifying defects that are poorly oriented or very small, such as high-temperature hydrogen attack (HTHA), but it avoids the problems associated with TOFD. The amplitude is still required to visually identify the phase changes to size defects.It’s impossible to locate a defect in the index axis without scanning multiple index positions.That said, TOFD has two main disadvantages: Such techniques are effective for identifying defects that are very small or in an orientation that has a poor response with the phased array (PA) technique. Ultrasonic testing (UT) users may be familiar with exploiting the signal phase information to identify and size defects using techniques such as time-of-flight diffraction (TOFD). Live 2D Images Using Signal Phase Information ![]() Here are 5 advantages that make this new inspection technique so powerful.ġ. In our testing, PCI has proven to provide excellent results for many challenging use cases, as well as improved results for common use cases such as weld inspections. This makes identifying defects very easy, especially for small defects in noisy or attenuative materials. Reflections and diffractions from defects result in a coherent response, compared with the incoherent response of acquired signals from high-frequency background noise.For a given position, the higher the level of coherence between the A-scans, the stronger the signal response for that position (with a maximum of 100%).Then, the phase distribution of each A-scan is compared for each position in the TFM zone.First, the acquired A-scans are normalized.Its signal processing is based exclusively on the phase information of the elementary A-scans used to generate a TFM image. How PCI Works and How It Differs from Other Ultrasonic Techniques As soon as your OmniScan X3 64 unit is updated, you can start taking advantage of PCI to achieve live total focusing method (TFM) images with unprecedented clarity and sensitivity to small defects. With the release of MXU 5.10 software, the OmniScan™ X3 64 flaw detector gains a new advanced ultrasonic inspection technique: phase coherence imaging (PCI).
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