Statistical Analysis of Contact-Induced Air Bearing Vibrations

Abstract

Air bearing vibrations at nanometer clearance levels are a major impediment to reducing head media spacing. Modern air bearings typically exhibit debilitating self-excited vibrations at fly heights of about 1–2 nm. At this point, peak head media spacing and contact pressures will increase, leading to performance and reliability issues. There has been considerable work performed to understand and improve air bearing stability at and around the point of contact, resulting in numerous experimental methods and design concepts in the literature. An area where additional research is worthwhile is the statistical behavior of contact vibrations. This paper explores the time dependence of fly height by using a simplified 2D air bearing with a mechanics based contact simulation. A comparison with measurements of fly height vibration demonstrates the utility of the simplified model and underscores the importance of proper time scale considerations.