Western Digital (fremont), Inc.

Kenneth R Davies

Jagdeep S Buttar

David D Terrill

Xiaodong Che

Herman Ferrier

Head stack fixtures for securing head stack assemblies to spin stand testing systems, and spin stand testing systems incorporating such fixtures, are disclosed. Exemplary head stack fixtures comprise a base supporting a piezoelectric actuator. The base includes an attachment mechanism for securing the HSA in such a way that the HSA will pivot relative to the base. When the HSA is secured to the base, the piezoelectric actuator engages the HSA. The piezoelectric actuator is therefore able to pivot the HSA relative to the base for fine positioning of a head of the HSA.

Spin stand testing system with fine positioner for head stack assembly

A spin stand testing system is used to determine a positioning range of a microactuator disposed on a head gimbal assembly. The microactuator is configured to laterally translate a read sensor of a head of the head gimbal assembly through the positioning range. The spin stand testing system includes a disk having a track, and a secondary mover configured to laterally translate the head gimbal assembly. During testing, a feedback loop keeps the read sensor locked to the track. While the read sensor remains locked, the head gimbal assembly is translated laterally. The microactuator translates the read sensor in an opposite direction until the microactuator reaches an end of its range, which is determined by monitoring a signal. The amount of translation of the head gimbal assembly by the secondary mover when the signal indicates the end of the range is the measured positioning range in one direction.

Method for determining a microactuator range of movement

Methods of measuring position error due to pole tip protrusion are provided. In exemplary embodiments, a head having a write element is aligned to a track, and then pole tip protrusion is induced in the write element by writing to the track. The position error is measured after the pole tip protrusion has been induced. The position error can be measured just after the write element stops writing so that the position error is measured before the position error degrades or relaxes. Alignment of the head to the track, and measurement of the position error are accomplished while the head is over a servo segment of the track. The servo segment can be provided with separate alignment and evaluation portions for aligning the head and for measuring the position error, respectively. The alignment and evaluation portions can each encode two parallel sub-tracks, each with a different frequency.

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Gilroy, CA, United States of America

Kenneth R Davies