Although non-film X-ray imaging technologies have been available for many years, several factors have contributed to a slow adoption of these methods for final inspection of aerospace castings. Many of these factors relate to the standards that support and control the implantation of X-ray inspection in this as well as many other industries. The industry standards, including both ASTM practices and customer standards presume film radiography. While many of these include a phrase such as “non-film techniques may be used with customer approval,” it has not been clear either to suppliers nor customers, how that approval process should proceed. Not only has the process for controlling image acquisition presumed film radiography, but the process for interpreting those images, using film reference radiographs also presumes comparison to film production images.
Over the last few years, several factors have come together to change the landscape for digital radiography. Project teams working through ASTM and supported by US Department of Defense funding, most notably through the Metals Affordability Initiative, have succeeded in establishing guidelines and standards to support the implementation of digital radiography for final part acceptance in the aerospace investment casting industry. This paper will describe some of the developments in hardware and software, standards, and reference images that are leading to this change in inspection approach.