Load/unload measurements using laser doppler vibrometry and acoustic emission

The dynamics of the load/unload process are studied using a so-called ‘periscope approach’ which allows us to follow the slider motion during load/unload (L/UL) with the beam of a Laser Doppler Vibrometer (LDV). LDV signals and acoustic emission signals are obtained for three different slider airbearing designs and for load/unload conditions with different vertical velocities and spindle speeds. The load process is investigated statistically using the acoustic emission signal in order to determine the effect of vertical load speed and spindle speed on the probability of contacts between slider and disk. sults indicate that small vertical load speeds decrease the number of head/disk contacts, and that slider designs with a cavity centered close to the trailing edge enable a smooth unloading process.