Two dimensional X-ray inspection is a nondestructive technology which has been used for some decades in the electronics manufacturing sector and much longer in oil and gas and general engineering. However, 3-D industrial computed tomography (CT) has been very much confined to the R & D environment and, in the manufacturing sector, its application has often been restricted to structure and defect analysis of high value and/or complex components and new materials. However, recent automatization, speed and accuracy developments have now allowed the migration of CT technology to the production floor. There it can be used as a powerful quality control and process optimization tool, providing fast and accurate inspection and measurement of components which are difficult to examine using CMMs or conventional radiography. This article looks at some of those developments.
Although the medical sector was the major user of radiography for many years, it is interesting to note that one of the first demonstrations of the technology, by William Roentgen himself, was to show his colleagues a radiograph of a set of metal weights contained within a box. However, radiography as an industrial inspection tool only began in the early part of last century and its first official acknowledgement was gained in 1931, when the American Society of Mechanical Engineers (ASME) permitted X-ray approval of welded pressure vessels with standards which still exist to this day.