Optimal dimple point of SFF HDD suspension for improving the unloading performance

The hard disk drive (HDD) using load/unload (L/UL) technology includes the benefits which are increased areal density, reduced power consumption and improved shock resistance than those of contact-start-stop. Dynamic L/UL has been widely used in portable HDD and will become the key technology for developing the small form factor HDD. The main design objectives of the L/UL mechanisms are no slider-disk contact or no media damage even with contact during L/UL, and a smooth and short unloading process. In this paper, we focus on pitch static attitude (PSA), roll static attitude (RSA), force position and dimple point. PSA and RSA are very important parameters in L/UL system and stability of slider is mainly determined by PSA and RSA. Dimple point is also important indicator. Also, we should consider lift-off force. The lift-off force, defined as the minimum air bearing force, is another very important indicator of unloading performance. The large amplitude of lift-off force increases the ramp force, the unloading time, the slider oscillation and contact-possibility. Therefore, to minimize lift-off force, we find the robust dimple point in L/UL performance.

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