Air-bearing effects on actuated thermal pole-tip protrusion for hard disk drives

Flying height (FH) control sliders with thermal actuation have been introduced recently in commercial products.for compensating the static FH loss and reducing the risk of head-disk contacts. In. the research reported here, we investigated the ftccts of airbearing surface (ABS) designs on the thermal actuation. We created a three-dimensional finite element model of an entire slider with a detailed read/write transducer structure and conducted thermal-structural coupled-field analysis using velocity slip and temperature jump boundary conditions to formulate the heat transfer across the head-disk interface when a sliderflies over a spinning disk. An iteration procedure was used to obtain the equilibrium solutions. Four ABS designs with distinct features were simulated. We defined five measures of merit, including protrusion rate, actuation efficiency, power consumph. on, pressure peak, and temperature rise of the sensor to evaluate the peijbrmance of thermal actuation. It isfiound that the effect of the pressure is more significant than that of the FH on the heat conductionfirom the slider to the disk. The efficiencies of three conventional designs decrease as the FHs are continuously reduced. A new ABS design, called Scorpion III, is presented and demonstrates an overall enhancement, including virtually 100% efficiency with significantly less power consumption. Transient thermal analysis showed that it requires -I - 2 ms for the temperature to reach the steady-state values, and there is a trade-off between increasing the actuation bandwidth and decreasing the power consumption.