Vision-Assisted Vibration Analysis of Inhomogeneous Flexible Cables in Hard Disk Drives

Reduction of flexible cable vibrations has been one of the key engineering focuses for magnetic disk drives to meet subnanometer recording precision requirement. Common approach to reduce the vibrations is to adopt additional polyimide-like damping layer on underlying homogeneous flexible cable, adding in homogeneity long the cable´s dynamic loop. This paper investigates the effect of inhomogeneous composition along the cable´s dynamic loop on the cable´s vibration modes. The cable´s profiles are obtained by experimental image processing and used in the proposed finite element model. It is found that placement and design of the inhomogeneous composition such as the damping layer for passive vibration control or piezoelectric layer for active vibration control can significantly alter the cable´s modal responses, which potentially can be used to reduce transmission of the cable´s vibrations onto the rotary actuator.