Effect of mechanical parameters for loading contact and instability in HDD

Ramp L/UL (load/unload) technology becomes core technology in mobile HDD. However, ramp L/UL always has instability because structural limit should repeatedly move between a ramp with a disk. Sometimes, there is a slider-disk contact during L/UL process. In particular, the slider-disk contact during the loading process has a critical effect on HDI failure due to difference of impact force by much higher height level despite low frequency. In this paper, we analyzed the loading contact and instability generated by the slider-disk contact during the loading process. Also, the loading mechanism for height and tilt variations was analyzed. It was suggested that the reason for the loading contact and instability through the relation among mechanical parameters such as the height and tilt of a HSA (head stack assembly), a ramp and a disk. Therefore, it should be considered that the mechanical parameters such as the height and tilt of the HSA, the ramp and the disk including PSA/RSA in order to avoid the loading contact and instability and to improve the loading performance.