Managing Measurement Uncertainty |
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CGI Inspection
15161 Technology Dr.
Eden Prairie, MN, 55344
USA
 
Press release date: March 11, 2008
In metrology, measurement uncertainty and the resulting potential for error are always present. Regardless of the technology employed, there can be an accumulation of tolerance errors in each element of the measurement process that puts the reliability of the inspected dimension in doubt. According to NIST (National Institute of Standards and Technology), a quantitative statement of the measurement uncertainty should accompany all inspection data. Therefore, it is critical to manage uncertainty and to understand that the sources of error go beyond the measurement tool.
Minimizing and managing uncertainty requires a comprehensive view of the instrument, operator, part, methods and environment. Collectively, these elements contribute to the error in inspection. While controlling the variation of each of these influencers will reduce the error and make it more predictable, the best practice is to eliminate the influences altogether. Cross-Sectional Scanning does just that.
Cross-Sectional Scanning's published error range is 0.0008 inch (20 micron). Unlike the reported accuracy of CMMs and other 3D scanning technologies, this statement encompasses not only the metrology instrument variance but also every other element of the inspection process. Consequently, using Cross-Sectional Scanning for first article inspection, tooling verification or ongoing process control will yield inspection reports with a relatively higher degree of certainty.
Consider the uncertainty factors associated with other technologies. When inspecting with a CMM, variance is introduced by the machine, the methods and the operator. Even the design of a fixture, placement of the fixture or mounting of the part can introduce unwanted error. With 3D scanning technology, the potential for variance comes from the scanning hardware and the processing of the point cloud. Alignment of scans, elimination of noise and other operator influenced processes will yield varying results for the same part.
Cross-Sectional Scanning is different. The operator is removed from the uncertainty equation, fixtures are eliminated, scan alignment is unnecessary and noise is nonexistent. These factors, and others, make Cross-Sectional Scanning repeatable, reproducible and reliable. Uncertainty is minimized and confidence in measurement accuracy is maximized.
If you want the truth; if you need to minimize uncertainty; you need to take another look at Cross-Sectional Scanning. Contact me today at (800) 207-4318 or visit www.CGIInspection.com.
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