Flying height response to mechanical shock during operation of a magnetic hard disk drive

A complementary experimental and numerical study of fly height response to applied mechanical shock during disk drive operation is reported in this paper. Numerical predictions of dynamic fly height response at the slider close point, due to measured drive component response to externally applied mechanical shocks, are plotted versus time and versus input shock, and are compared,with the disk glide avalanche height. HDI contact pressure, as predicted using the Greenwood-Williamson contact model, is also plotted versus amplitude and sense of the externally applied mechanical shocks. The effects of measured disk motion on fly height response to operational shock are described and are shown to be significant. It is concluded that design changes that modify disk response can be a efficacious path for the disk drive designer to improve fly height response to operational shock.