Slider–bump contact and flying height calibration

Abstract

It is a big challenge to determine ultra-low slider flying height accurately. The standard bump disk method is probably the most reliable and acceptable method so far. One of the key issues to determine slider-flying height with the bump disk method is the complicated slider-bump interaction process and the possible disturbance of the bumps on the slider flying performance. Our knowledge about the slider-bump interaction process is still very limited due to the lack of an effective and powerful experimental technique to study it. In this work, the slider-bump interaction process was studied with a dynamic flying height-attitude (3D) system. The interaction process was also simulated to compare with the experimental observations and to help determine the sliderbump contact points in the experimental observations. The accuracy of flying height (FH) calibration with the bump disk method and the minimum slider-bump interference height required for the testing system used in this study to detect the onset of sliderbump contact were analyzed and discussed. It is proved that the 3D system is a very useful and powerful tool for the application. Many details of the slider-bump interaction process can be revealed with the 3D system. It is found that the calibrated FH is much more accurate than that predicated by the simulations.

Improving Hard Disk Drive Unloading Performance With a Disk Bump

“…The laser beam method is widely used to make disk bumps, and there has been much research into using this method [9]- [11]. However, we used mechanical pressing because of the bump dimensions required.…”

Design-oriented prediction of operational shock and vibration for hard disk drives

“…Each existing experimental technique has one or two weaknesses that limit their ability to measure/identify the slider-disk contact due to external shock. Most of precision instruments, such as interferometers [170][171][172][173] can operate accurately only when the rigid body motion of the measured object is relatively small. Measurement techniques using acoustic [174,175] require quiet environment to detect the occurrence of contacts.…”