Operational Shock Analysis for 2.5-in Multi-Disk HDD Considering Ramp-Disk Gap Irregularity

With an increased mobility, hard disk drives (HDDs) now use ramp load/unload technology, and multiple disks are used to increase the data capacity. This can result in contact between the ramp and the disks, which negatively affects the slider dynamics under operational shock conditions. There are several types of ramp-disk contact, such as simultaneous, successive, and single contact, and these depend on the distance between the ramp and each disk in a multi-disk HDD. This paper examines the effect of ramp-disk contact on the slider dynamics using a transient shock analysis. The ramp-disk contact affects the head stack assembly bending mode and slider dynamics. The effect of irregular gaps between the disks and adjacent ramp on the slider dynamics is analyzed with the ramp-disk contact force. The simulation shows that the gap irregularity between the ramp and each disk should be as small as possible to improve the stability of the slider dynamics.