Ramp load/unload (L/UL) mechanisms are widely used to rest sliders in hard disk drives (HDDs).
Loading/unloading a slider swiftly and smoothly is crucial in a HDD design. A novel, efficient
simulation scheme is proposed to investigate the behaviors of a head disk interface (HDI) in
ramp unloading processes. A dual scale model is enabled by decoupling the nano-meter scale change
of an air bearing and the micro- or milli-meter scale deformation of a suspension. A modified
Reynolds equation governing the air bearing was solved numerically. The slider design was
characterized with performance functions. Three stages in an unloading process were analyzed
with a lumped parameter suspension model. Key parameters for the model were estimated with a
comprehensive finite element suspension model. Finally, simulation results are presented for
a commercial HDI design.