Interferometric ball bearing test station

Abstract

Method and apparatus for determining if a surface of an object, such as a ball bearing (12), has a radius of curvature within a predetermined tolerance. A test system (10) includes an interferometer having a reference beam (20a) and a measurement beam (20b). The measurement beam is disposed for illuminating a surface of the object while the object is in motion. A cylindrical lens (24) is provided for forming the measurement beam into a linear, stripe-like pattern that illuminates the surface. The measurement beam reflects from the surface of the object to a beamsplitter (20) that combines the reflected measurement beam with a reflected reference beam. The test system further includes an imager (30), optically coupled to an output of the interferometer, for recording a two dimensional interferogram that results from a change in an optical path length of the measurement beam relative to an optical path length of the reference beam. The test system further includes a processor (32), coupled to an output of the imager, for comparing the interferogram recorded by the imager to a reference interferogram previously recorded from a surface of an object known to have a radius of curvature within the predetermined tolerance.

Dependencies are inferred from the claim text.