We discuss the measurement of diameter and form of micro-holes with reverse tapers in a fuel injector nozzle using an ultra-low force contact fiber probe on a CMM. The fiber probe was designed and built at the National Institute of Standards and Technology (NIST) and has demonstrated extremely low uncertainties (under 100 nm, k = 2) on high-quality artifacts. We present diameter and form data, and detail an uncertainty budget for the diameter. The dominant terms in the uncertainty budget are related to the poor surface finish and form of the part. Our uncertainty budget indicates that the diameter of a suitably clean micro-hole in a fuel nozzle can be determined to an uncertainty of 196 nm (k = 2) with our probing technique.
Proceedings Title: American Society for Precision Engineering, Annual Meeting 2009
Conference Dates: October 6-8, 2009
Conference Location: Monterey, CA
Conference Title: Proceedings of the Annual Meeting of the American Society for Precision Engineering, Monterey CA 2009
Pub Type: Conferences
Fiber probe, Fuel injector nozzle, Micro-hole metrology