A comparison of reversal and multiprobe error separation

This paper demonstrates the application of two methods of separating spindle error motion from artifact roundness on a spindle with <<5 nm radial error. Two error separation methods, reversal and multiprobe, were each applied to data taken on two different test stands allowing direct comparison of the four combinations of hardware and separation algorithm. Because the theory of both separation methods is well documented, this work focuses on their implementation for nanometer-level measurements. As will be seen, a number of issues must be addressed to obtain repeatable results at this level of precision in spindle metrology. Ultimately, the results show that sub-nanometer features in both spindle error and artifact form can be reliably and repeatably resolved by both techniques.