Effective Optimum Design of Negative Pressure Slider for Load/Unload Applications

This paper focuses on slider air bearing design in order to reduce the lift-off force during the unloading process while satisfying the desired static flying performances. Since it takes a huge amount of computational time to solve time-dependent dynamic L/UL equations, a simplified lift-off force model with respect to air bearing suction force and flying attitudes is created by the kriging method. The EMDIOS is employed as a design framework to wrap effectively and connect the analyzers to the optimizer. In this study, an optimization problem is formulated to minimize the amplitude of lift-off force during unloading process while keeping the flying height, pitch and roll angles within suitable ranges over the entire recording band as well as reducing the possibility of slider-disk contact in steady state. From a conventional negative pressure slider, a modified slider model is optimally designed for 1-inch disk drive with L/UL system. The simulation results show that the lift-off force can be reduced by about 60% in comparison with that of the initial design. It is demonstrated by the dynamic L/UL simulation that the optimum slider incorporated with the suspension is not only smoothly loaded onto the rotating disk, but also properly unloaded onto the ramp. It is proven that the proposed design approach, which uses a static analysis instead of a time-dependent dynamic L/UL analysis during iterative optimization process, works efficiently in designing a slider air bearing for L/UL applications.