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Fiber Deflection Probe for Small Hole Metrology



Balasubramanian Muralikrishnan, Jack A. Stone Jr., John R. Stoup


This paper presents the development of a new probing method for Coordinate Measuring Machines (CMM) to inspect diameter and form of small holes. The technique, referred to as fiber deflection probing, can be used for holes of approximately 100 mm nominal diameter. The expanded uncertainty obtained using this method is 0.07 mm (k = 2) on diameter. The probing system consists of a transversely illuminated fiber (with a ball mounted on the end) whose shadows are imaged using a camera. This method of shadow imaging provides the magnitude of fiber deflection which is then used to correct final machine coordinates to obtain coordinates on the surface. In this paper, we describe the measurement principle and provide an analysis of the imaging process. Subsequently we discuss data obtained from characterization and validation experiments. Finally we present results from small hole measurements and provide an uncertainty budget for diameter measurements.
J. International Societies for Precision Engineering and Nanotechnology


coordinate metrology, fiber probe, microfeature metrology, small hole


Muralikrishnan, B. , Stone, J. and Stoup, J. (2006), Fiber Deflection Probe for Small Hole Metrology, J. International Societies for Precision Engineering and Nanotechnology, [online], (Accessed April 23, 2024)
Created January 1, 2006, Updated February 19, 2017