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Proceedings Paper

NDE process control using DR and CT x-ray techniques
Author(s): Francis H. Little; John Janning
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Paper Abstract

Digital Radiography (DR) and Computed Tomography (CT) imaging has historically has been used to evaluate parts for indication of density variation The images were displayed on a workstation and were evaluated for flaws and non-conforming indications. The next step was to perform elementary measurements, statistic, graphical, etc. by operating on the digital data using the computer. Finally, the complete 3D model was constructed from contiguous CT images to defines the part in 3D. Since this is the 3D definition of the part, the next logical step is to extract geometry definition similar to a CAD model. GE has developed algorithms and methods to obtain geometry definition of parts using both Digital Radiography and Computed Tomography x-ray inspection techniques (referred to as X-ray Metrology). CT imaging yields a complete 3D model of the part with a sacrifice of time, whereas multiple DR (2.5D) imaging is acquired must more rapidly with a sacrifice of volumetric information. Where the characteristics can be defined with 2.5D, this method can be used in more nearly real time applications. Originally, GE used X-ray Metrology information to reverse engineer the part where only partial CAD data exits To completely reverse engineer a part, extensive manual labor is required if the geometry is complex as for the turbine blade. As more parts are being designed using 3D solid modeling, there will be less need for reverse engineering. But, X-ray Metrology can have a very important role in part development and process control. GE is successfully using X-ray Metrology to extract part geometry and perform sampling process monitoring. X-ray Metrology provides geometry definition of the part both inside and outside with out destroying the inspected part. The increased computer system performance has enable the rapid generation of large x-ray data set from image processing. In some cases, commercially available software has enabled manipulation of the x-ray data to assist in filtering the data into process control formats.

Paper Details

Date Published: 15 November 1996
PDF: 2 pages
Proc. SPIE 2948, Nondestructive Evaluation for Process Control in Manufacturing, (15 November 1996); doi: 10.1117/12.259202
Show Author Affiliations
Francis H. Little, GE Aircraft Engines (United States)
John Janning, GE Aircraft Engines (United States)

Published in SPIE Proceedings Vol. 2948:
Nondestructive Evaluation for Process Control in Manufacturing
Richard H. Bossi; Tom Moran, Editor(s)

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