Load/unload investigations on a rotary actuator disk drive

Head-disk contacts in a disk file with a rotary actuator are examined during load/unload using laser Doppler vibrometry and acoustic emission techniques. A novel scheme that allows tracking of the slider with the laser beam of a laser Doppler vibrometer during load/unload is implemented. Head-disk contacts are found to occur as a function of the velocity of the slider along the inclined ramp prior to loading, and it is shown that a low vertical loading velocity is less likely to introduce head-disk contacts than a high loading velocity. For the swing-arm actuated drive investigated, head-disk contacts start to appear at loading velocities as low as 25 mm/s. A careful design of the tip of the ramp is of utmost importance in ramp loading mechanisms to reduce the effective vertical component of the slider as it comes off the tip of the ramp during loading