Design and analysis of disk bump to improve the unloading performance in hard disk drives

Most hard disk drives that apply the ramp load/unload technology unload the heads at the outer edge of the disk while the disk is rotating. During the unloading process, slider-disk contacts may occur by lift-off force and rebound of the slider. The main issue of this paper is to prevent the slider-disk contact by rebound, and we apply a disk bump to the unloading process. To do so, first, the ranges of bump dimension are determined. Second, the stability of each bump is checked by dynamic simulation. Finally, unload analyses are performed for stable bump designs. As a result of these analyses, we investigate proper bump design and position for the unloading process. Through this research, we propose the optimal bump design to improve the unloading performance. We can also identify to remove rebound contact by applying a bump on disk to the unloading process.