Alternation of Flex Cable Vibration Modes in High Precision Hard Disk Drives

Flex circuits are a laminate of polyimide substrate, adhesive, and copper conductors, and they are used to connect the (stationary) electronic components in a hard disk drive to the (rotating) arm that positions the read/write heads above the disk. The transverse and longitudinal vibration of flex circuits couples with motion of the read/write heads and contributes to increased settling time and residual vibration following repositioning of the arm from one data track to another. In this paper, the results of parameter, optimization, and experimental studies are discussed with a view toward increasing the isolation of vibration between the flex circuit to the arm in terms of a metric involving one or several important vibration modes.

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A PASSIVE DAMPER FOR THE VIBRATION MODES OF THE HEAD ACTUATOR IN HARD DISK DRIVES

Journal of Sound and Vibration ◽

10.1006/jsvi.1998.1940 ◽

1999 ◽

Vol 220 (4) ◽

pp. 683-694 ◽

Cited By ~ 18

Author(s):

L. Jiang ◽

R.N. Miles

Keyword(s):

Hard Disk Drives ◽

Hard Disk ◽

Vibration Modes ◽

Disk Drives ◽

Passive Damper

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Effect of the pivot assembly on the dynamic behaviour of a head actuator in hard disk drives

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/0954406011520887 ◽

2001 ◽

Vol 215 (4) ◽

pp. 461-467 ◽

Cited By ~ 1

Author(s):

P Gao ◽

L Xu ◽

R Lin ◽

H Tan

Keyword(s):

Dynamic Behaviour ◽

Mechanical Design ◽

Hard Disk Drives ◽

Hard Disk ◽

Laser Sensor ◽

Vibration Modes ◽

Disk Drives ◽

Experimental Demonstration ◽

Element Analysis ◽

Vibration Dynamics

Vibration/dynamics studies have become increasingly important in the mechanical design of hard disk drives (HDDs) owing to the ever-growing demand for greater storage density and access speed. In fact, it is anticipated that it is the vibration/dynamic characteristics of HDD assemblies that will eventually pose a design limit on their performance, not the associated electronics whose designs are far more advanced. In this study, finite element analysis is used to model and investigate the dynamic behaviour of a head actuator with consideration of the effect of pivot assembly. Then, an experimental method for measuring the vibration/dynamics of the head actuator is developed using the Ometron VPI laser sensor system. The representative vibration modes that limit the servo bandwidth are identified and analysed. The effect of pivot assembly on the vibration modes of the head actuator is studied under different conditions. From the results of numerical analysis and experimental demonstration, it is shown that pivot assembly is an important factor that limits the servo bandwidth and access speed of the head actuator. Based on these studies, a new passive damping structure, which is attached to the housing of the pivot assembly, is proposed, and its feasibility for improving the dynamic behaviour of the head actuator is theoretically proved.

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