Researchers at the Fraunhofer Institute for Nondestructive Testing IZFP, Germany, have developed an ultrasonic phased-array instrument that enables them to produce high-resolution 3D images. In phased array technology, several single-element probes are arranged side by side into rows or sheets. This allows the ultrasonic waves to be passed through large areas of material at a time instead of only penetrating the subject selectively.
Fraunhofer IZFP scientists have developed this idea further by making it possible to control each probe separately, allowing examiners to focus on every part of the area being tested simultaneously. In parallel, they have developed an algorithm that generates a 3D image from the many individual signals that can then be viewed on a PC.
“The spatial resolution of these images is significantly better than in conventional methods. What’s more, our reconstruction algorithm is real-time capable, which allows us to significantly speed up the testing process,” says Professor Hans Georg Herrmann.
Another plus: The new, robot-assisted process can even test materials that have historically been difficult to characterize. Inspecting fiber-reinforced high-performance polymers with direction-dependent fiber orientation is typical of the applications suitable for this new testing technology.
To analyze an abnormality in the material, the examiner can view the pictures from different directions, rotate them or select specific areas. It is also possible to take longitudinal or transverse sections of the images. The objective for industrial applications is to achieve largely automated component testing by enabling an industrial robot, connected to the inspection system via an interface, to carry out complete component scans.
