3-Reversals and Error Separation (Half-Day, Hybrid)
Dr. Christopher J. Evans (University of North Carolina – Charlotte) & Dr. Vivek G. Badami (Zygo Corporation)
Monday, November 4, 2024 (8:00 AM – 12:00 Noon)
Most measurements rely on a comparison of the part under test with a calibrated artifact. The reported measurement result has a bias depending on the convolution of any bias in the calibration with deviation from nominal in the part. A number of methods can be used to reduce these bias terms.
In dimensional metrology of part feature many techniques have been developed for accurate measurement of part features without reference to an externally calibrated artifact. This tutorial will present a partial survey of such methods for dimensional metrology, their ranges of applications, and their limits. A broad range of applications will be covered, including methods for flatness, squareness, straightness, level, probe ball calibration, and angle and linear scale calibration. The tutorial also attempts to distill the common features of the various methods in the hope that this may provide the basis, or inspiration, for the development of “new” reversals or aid the development of new combinations of techniques to address specific metrology problems. All techniques will be covered first at the conceptual, mechanistic level; then each will be treated with appropriate analytical tools. Most techniques require no more than simple algebra and trigonometry; a small percentage requires mathematical skills typical for graduate engineers.
About the Instructors
Dr. Chris Evans is Professor Emeritus in the department of Mechanical Engineering and Enginering Science at UNC-Charlotte where he was previously Director for the Center for Precision Metrology. Before that he worked at Zygo Corp and the National Institute of Standards and Technology. He is active in both precision manufacturing and metrology.
Dr. Vivek Badami is currently the Director of Engineering for the Optical Systems Group at Zygo Corporation where he oversees and participates in the development of advanced optical systems of all kinds. He is also a Technology Fellow and works on precision engineering challenges across the entire organization. Vivek is involved in the precision engineering and metrology communities and actively participates in the mentoring and education of young engineers in the art and science of precision engineering. He is a Fellow of the American Society for Precision Engineering (ASPE), past president of the Society, and has served the Society in various capacities, including as Associate Editor for the international journal of the Society, Precision Engineering. He has authored several technical papers, a book chapter and holds several patents. Vivek obtained his doctorate from the Center for Precision Metrology at the University of North Carolina at Charlotte in 1999, where he is also an Adjunct Professor in the Department of Mechanical Engineering and Engineering Science.