Recent Advances in Non-Destructive Examination: Enhancing Inspection Efficiency
Introduction
Non-Destructive Examination (NDE) has evolved significantly as an inspection discipline. The progression of NDE technologies now addresses new challenges posed by novel materials and complex material geometries. This article examines recent advancements in various NDE modalities that have enhanced the accuracy, speed, and interpretability of inspections.
Historical Context and Technological Progress
NDE's initial methodologies—radiography, ultrasonics, and visual inspection—relied heavily on the expertise of inspectors for data interpretation. Radiography, for instance, utilized wet film that required skilled evaluation. Ultrasonic inspections were conducted using the pulse-echo technique, demanding expert interpretation of A-scans, B-scans, and C-scans on oscilloscopes. Visual inspections often involved only a brief examination of welds or boilers to detect flaws. However, advancements in computing power have significantly refined data interpretation, reducing the dependence on expert judgment. Modern systems now generate reliable, easy-to-understand inspection results in real-time, eliminating the need for extensive expertise.
Advancements in Ultrasonic Inspection
Ultrasonic (UT) inspection originally employed a basic pulse-echo technique, where sound waves reflected from flaws produced an image indicating the flaw's location and size. The introduction of Time of Flight Diffraction (TOFD) and phased array technologies has markedly improved both accuracy and speed. Nevertheless, expert interpretation is often still necessary.
Phased array systems utilize computer-controlled excitation of each element in a multi-element probe. By adjusting the amplitude and timing of these elements, a focused, steerable beam is generated. This allows for inspections at various angles and depths almost simultaneously. A single phased array probe can thus perform tasks that would typically require multiple conventional probes or several scanning passes. Although TOFD probes are compatible with phased array systems, conventional pulse-echo methods are predominantly used, wherein the dB drop technique is employed to size and visualize flaws. However, this method often produces more data than current UT flaw detectors can process efficiently, leading to simplified data projection and the need for remote expert analysis.
Recent advancements in ultrasonic systems with enhanced computing power now enable the creation of volume-corrected images directly on the inspector’s device. This innovation, coupled with volume-based statistical measurements, has streamlined defect sizing and interpretation, significantly improving inspection efficiency.
Remote Visual Inspection: A New Standard
Remote Visual Inspection (RVI) is increasingly prevalent across various engineering sectors. The advent of the first HD 3D measurement-enabled portable video borescope represents a significant leap forward, offering superior HD quality and accuracy in a rugged, lightweight design suitable for the harshest environments.
The exceptional HD quality of this new instrument is attributable to its high-intensity light source and advanced visual processing capabilities, which deliver clearer, sharper videos and still images directly to the device. This technology, which does not require multiple tip changes, enhances measurement accuracy over greater distances and enlarges the measurement surface area. The integrated HD digital zoom facilitates the inspection of very small indications, while on-demand 3D Phase and Stereo Measurement offer detailed analysis and mapping capabilities, enabling faster and more informed asset decisions.
Computed Tomography: Transitioning from Laboratory to Production
Computed Tomography (CT) has evolved from a laboratory-based technology into a critical tool for process control, particularly in the aerospace, automotive, and additive manufacturing industries. Innovations in CT technology have drastically reduced inspection times, achieving results in minutes rather than hours, without compromising quality.
Recent developments include the introduction of scatter radiation artifact correction, allowing the efficient use of cone beam CT instead of traditional fan beam CT. By automatically eliminating most cone beam scatter artifacts, this technology achieves image quality comparable to fan beam scanning but at speeds up to 100 times faster. Additionally, the next generation of high dynamic flat panel X-ray detectors combines enhanced pixel size with improved efficiency and sensitivity, resulting in higher resolution without increasing cycle times.
CT’s role in dimensional metrology is also expanding, especially for complex parts with inaccessible internal surfaces. CT allows for nominal-actual CAD comparisons, wall thickness analysis, and precise dimensional measurements, even on hidden surfaces. Advanced metrology techniques, such as automated calibration and thermal drift compensation, have enabled CT systems to achieve accuracy levels of less than 4 microns.
Industrial Volumetric CT: Integration with Robotics
The integration of CT technology with automated manufacturing processes is exemplified by a fully automated CT inspection line in Asheville, NC, dedicated to producing ceramic matrix composite (CMC) components for the aerospace sector. This system, which includes fully autonomous robotic handling, has significantly reduced inspection times and is scalable to meet future production demands.
CT in Electronics Manufacturing
While CT has traditionally been used in aerospace and automotive sectors, it is now increasingly employed in electronics manufacturing, driven by the complexities of e-mobility and advanced electronic components. High-resolution CT NDE is now standard for inspecting semiconductor chips, high-end electronic assemblies, sensors, and lithium-ion batteries. To address the growing importance of this sector, Waygate Technologies has established a Customer Solutions Center in Seoul, South Korea, dedicated to providing advanced CT inspection solutions for the battery, electronics, and automotive industries.
Enhancing Digital Field Radiography
Digital field radiography encompasses on-site radiographic methods, from film digitization to computed radiography and direct digital radiography. Recent software advancements have maximized the capabilities of portable radiographic imaging systems. The new Rhythm RT software platform, built on 15 years of expertise and customer insights, offers an intuitive touch interface that simplifies operation and enhances efficiency with minimal operator training.
The platform's scalable architecture allows for easy modification of software features without requiring code changes. Inspection data can be swiftly shared for remote expert assessment, and DICONDE-compliance ensures the longevity of data.
Rhythm RT also includes Flash! image processing, capable of performing billions of calculations per image. This tool adds a layer to raw images, automatically processing and clarifying them with a single click. The technology merges details from high- and low-density areas into a single HD image optimized for human analysis, expediting defect detection and improving coverage without altering the raw inspection data.
Conclusion
NDE, often viewed as a costly add-on, is crucial for ensuring the fitness-for-purpose, customer satisfaction, and operational safety of products. The migration of CT from research and quality labs to production floors offers significant opportunities for 100% control of complex components, such as additive manufactured parts and aerospace components. This migration also facilitates the generation of statistical 3D data, enabling immediate process optimization to enhance productivity and product quality.
Therefore, it is imperative that NDE tools and systems offer the highest probability of detection and accuracy, while also providing data that is easy to interpret. Recent advancements in NDE technology continue to push the boundaries, striving to meet these critical objectives.