Dynamics of inline flying-head assemblies

Heads for high-performance disk storage must be able to withstand an acceleration of dozens of G-force and be capable of positioning to submicron precision. A measuring technique that can totally analyze the flight stability and access ability of the slider was developed. It involves three-dimensional modal analysis of the suspension using a laser Doppler anemometer, a laser Doppler vibrometer, and simultaneous measurement of spacing fluctuation. Using this system to examine an inline head, it was found that notable lateral and torsional modes of the suspension vibration were caused by the access acceleration of the rectangular wave, and that there is pronounced spacing fluctuation. In addition, these lateral vibrations cause the pivot to slip, which may cause problems in high-speed head access