Experimental and Analytical Study of Bouncing Vibrations of a Flying Head Slider in a Near-Contact Regime

This paper presents an experimental and analytical study of bouncing vibrations of a flying head slider in near-contact and contact regimes. In our experiment we showed that, by reducing the ambient pressure, the slider begins to touch-down and exhibit bouncing vibrations, and by increasing the ambient pressure thereafter, the slider continues to vibrate until an ambient pressure higher than the touch-down pressure. In the analysis we used a two-degrees-of-freedom slider model with linear front and rear air-bearing springs and dashpots. In a numerical simulation of slider dynamics, we considered rough surface contact of the trailing air-bearing pad with a disk, including bulk deformation, adhesion force of lubricant and friction force. The disk is assumed to have no microwaviness. From the simulation of decreasing and increasing nominal flying height, we found that the slider exhibits a bouncing vibration and touch-down/take-off hysteresis as seen in the experiment. The frequency spectrum characteristics of the bouncing vibration agree well between numerical analysis and the experiment. From a parametric study of the bouncing vibration excited by initial spacing deviation, we found that the unstable flying height range can be decreased by increasing the air-bearing stiffness and can be completely eliminated if the lubricant adhesion force or the frictional coefficient is decreased to certain small values.