Patent ID: 6441998
Filing Date: 2002-08-27
Classification: G11B,Y10T

Abstract:
A method of designing an actuator arm of a head stack assembly for use in a disk drive comprising a disk, the actuator arm for positioning a head over the disk while the disk is rotating at a selected spin-rate, the actuator arm having a leading edge and a trailing edge and a selected thickness, the head stack assembly having a structural resonance frequency, the method comprising the steps of:(a) rotating the disk such that the disk generates air flow around the actuator arm while the disk is spinning at the selected spin-rate; (b) controlling the actuator arm to position the head over the disk while the disk is spinning at the selected spin-rate, wherein the air flow travels from the leading edge to the trailing edge of the actuator arm such that the air flow causes vortex shedding at a vortex shedding frequency resulting in an undesirable force being applied to the actuator arm when the vortex shedding frequency is aligned with the structural resonance frequency; (c) measuring a perturbing effect due to the undesirable force applied to the actuator arm; (d) modifying the thickness of the actuator arm and storing thickness data; (e) repeating steps (b)-(d) at least once; and (f) selecting a manufacturing thickness for the actuator arm from the stored thickness data to compensate for the undesirable force that is applied to the actuator arm due to the vortex shedding.