Air Film Dynamics for Micro-Textured Flying Head Slider Bearings in Magnetic Hard Disk Drives

This paper describes the air film dynamics for micro-textured flying head slider bearings in magnetic hard disk drives and it discusses their ability to increase the air film damping. In order to study the effects of micro-textures on air film dynamic characteristics of flying head slider bearings, two-dimensional micro-textures are modeled as deterministic rectangular models in the transverse and longitudinal directions. Dynamic analysis of these micro-textured flying head slider bearings is carried out by computing the impulse responses of the sliders and applying the modal analysis method to obtain their modal frequencies, damping ratios, and mode shapes. It is found that micro-textures on air bearing surfaces in the transverse direction have very significant effects and increase the air film damping of the slider’s three vibration modes but do not affect the air film stiffness. The same is not true for micro-texture in the longitudinal direction. The effects of transverse micro-textures’ spacing and depth on the air film dynamics are also numerically investigated in detail. The optimum values for high air film damping ratios are obtained. It is found that transverse micro-textures having small spacing are not very effective, being equivalent to the surface roughness effect.