Load/unload measurements using laser doppler vibrometry and acoustic emission

The dynamics of the load/unload process are studied using a so-called 'peri scope approach' which allows us to follow the slider motion during load/unl oad (L/UL) with the beam of a Laser Doppler Vibrometer (LDV). LDV signals a nd acoustic emission signals are obtained for three different slider airbea ring designs and for load/unload conditions with different vertical velocit ies and spindle speeds. The load process is investigated statistically usin g 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. The results indicate that small vertical load speeds decrease the number of head/disk contacts, and that slider designs with a cavity centered close t o the trailing edge enable a smooth unloading process. (C) 2000 Elsevier Sc ience Ltd. All rights reserved.