Aiding this reduction in time is the growing use of robotics. The simplest robotic radiographic inspection is exemplified by a conveyor belt moving engine blocks past an X-ray source on one side and a detector on the other. An operator reads a viewer as the specimens pass by. More complex systems required for more complex objects make use of a manipulator for the object itself and another for the X-ray source and the detector. These systems are computer programmed to maintain the correct positions, distances, and levels of energy and intensity to create the required image.
The ideal candidate for robotic application is neither a simple, regular geometric form nor a highly complex and irregular casting. With the former, there is no need for a robot. The conveyor-belt model referenced previously would be adequate. With the latter, more sophisticated programming and articulation would be required than is currently available.
It is metal castings with a basic cylindrical shape, but irregular configurations such as those found in bosses, fins and fittings, that lend themselves well to robotics. A good example would be the stators, rotors, fan frames and compressor cases that make up the components of jet engines.
In fact, the aerospace industry-long reluctant to develop standards for digital and robotic radiography-has recently started to certify certain applications on a cautious, case-by-case basis. Thus, a large jet-engine component can be made to rotate on its axis at any angle desired with its wall positioned between a radiographic source on one robotic arm and a digital detector on another with the entire process computer programmed to move robotically.
In another application, many of the blades that make up a compressor for a jet engine are fixed in a circle so that the robotically-controlled radiographic apparatus can create images quickly, reliably and repeatedly in a controlled, autonomous fashion. Efficiencies are realized in many successive areas including: