Improving Hard Disk Drive Unloading Performance With a Disk Bump

Most hard disk drives use ramp load/unload (L/UL) technology because of its many advantages. However, L/UL does have some unresolved drawbacks, such as slider-disk contact during fast unloading. The main objective of our research is to examine the use of a bump on the outer edge of the disk to prevent contact with the disk by the rebounding slider and to improve ramp unloading performance. In particular, this paper focuses on experimental verification of the design of the disk bump that resulted from our previous research. We formed the disk bump on the disk surface using mechanical pressing with tungsten tips and tested the effect of the bump in unloading experiments. An investigation of the acoustic emission burst signal and its power spectrum confirmed that the optimal disk bump prevented slider-disk contact. This improves the ramp unloading performance.