Slider–bump contact and flying height calibration

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 slider–bump 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 slider–bump 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.