DESIGN AND OPTIMIZATION OF A HARD DISK DRIVE SUSPENSION

Abstract

A hard disk suspension is essentially a cantilever beam with a read/write head attached to its tip. In achieving faster seek time and higher recording density, the suspension needs to have a high off-track resonance frequency . At the same time, it is required that the suspension should not be overly stiff in bending. A tapered beam structure is a common design for the suspension. This project therefore seeks to enhance the current design with a rib built along the line of symmetry of the suspension. To obtain the best performance of this design, parametric studies are conducted analytically using beam theory and numerically through sensitivity analysis. Sequential quadratic programming is then used to optimize the suspension. The optimized design is able to attain a first off-track resonance frequency of 15khz while limiting the bending stiffness to 40N/m. This is 50% higher than the current commercial design. Experimental modal analysis is also carried out using a laser doppler vibrometer (LDV) to verify the numerical results. Results from the experiment are found to be in good agreement with the numerical results. In summary, suspensions with ribs are proven numerically and experimentally to have a higher off-track resonance frequency than the current design.