Connect, no.148, May/June 2007, p.6
Phasec 2d portable dual phase eddy current inspection system in use for inspecting a turbine disc
Since its opening in 2003, TWI Wales has reinforced its position as a world leading resource for research and development of advanced non-destructive testing (NDT) techniques. Through continued investment in leading edge equipment,and high calibre staff, the acknowledged centre of excellence has gone from strength to strength. Investment in the high tech equipment has been made possible through sources of regional funding in the South Wales region, and thefacilities complement those at the company's headquarters in Cambridge.
The particular strengths of the centre are radiographic and non-contact inspection techniques, and the predominant industry focus for the centre is split between aerospace and microtechnology; two areas of particular importance inthe South Wales region.
The quality of digital radiography has improved significantly in recent years and TWI's capabilities lie in the areas of microfocus radiography and computed tomography.
The equipment available for microfocus radiography is able to detect flaws on a micrometre scale, making it suitable for inspecting small components and, in particular, printed circuit boards and other electronic components.
Ultrasonic Sciences immersion UT system being used to inspect a cylindrical metal billet to detect embedded inclusions
Computed tomography is used to build up 3D images of components from a large number of 2D radiographic images taken around a single axis of rotation. The 3D image can be 'sliced' to permit inspection of internal features, as if themodel has been produced using CAD software.
The equipment available at TWI Wales can penetrate 110mm of steel or 300mm of aluminium, although the technique is often applied to composite structures, using much lower x-ray energies. A full 3D model of a component can begenerated in around 40 minutes -, but the data-set contains far more information on the internal structure than would be available from conventional radiography.
The computed tomography method is also used for microfocus radiography, meaning that small parts and electronic components can be treated in the same way and inspected for internal defects, and to map internal structure anddimensions.
In the area of non-contact inspection technology, methods such as laser shearography, thermography, automated optical imaging, eddy current arrays, moiré interferometry and laser generated ultrasonics are all available at TWIWales. Experts in these subjects carry out research and contract work for organisations from a wide range of industries, including aerospace, power generation and oil and gas.
These techniques enhance inspection potential in terms of the types of defects detected, the accuracy, consistency and speed of inspection, suitable materials, and complexity of structures.
