Hitachi Global Storage Technologies Netherlands B.v.

Norman Chu

Hang Fai Ngo

Bradley Frederick Baumgartner

Patricia Galindo

Shanlin Duan

Yu Lo

Nalin Zhou

Charles Chung Lee

Bob Clyde Robinson

Tony Mello

Christopher Ramm

Parul Agrawal

Connie H Moy

An-Chou Andrew Chen

Roger Yu Lo

A glide head calibration technique uses two fly height calibrations on a disk media certifier. The first calibration point uses a spin down on bump technique at a first height, and the second calibration point uses a spin down on disk media roughness at a second lower height. With two height data points, a fly height curve of each glide head is approximated very accurately. Once the fly height curve is derived for each head, any fly height can be dialed-in by the disk media certifier for glide testing. This technique achieves glide fly heights between about 4 nm and 8 nm and does so with improved tolerances.

System, method, and apparatus for glide head calibration with enhanced PZT channel for very low qualification glide heights

A method is presented for glide testing a disk which tests the glide head fly-height by inducing a collision between the glide head and a disk under test. The glide test system is initially calibrated using calibration disks. The method of the invention periodically tests the calibration without interrupting the production testing by lowering the rotation rate until the glide head collides with the rotating disk surface. The rotation rate at which the collision occurs is then compared with the value expected based on knowledge of disk samples and the initial calibration. Parameters for acceptable high and low values are established to detect changes in the glide test system performance to trigger automatic or manual recalibration.

Glide testing of disks with calibration confirmation testing by inducing collision of the slider with production disk surface

An in-situ technique for the acoustic emission monitoring of burnish heads while they are cleaning or burnishing magnetic media is described. The burnishing process is monitored and controlled to identify interaction or contact between the head and media due to, for example, burnish head damage, substrate curvature problems, and lube pick-up problems. A piezoelectric sensor is mounted on the burnish arm that holds the burnish heads. When head-disk interaction occurs, stress waves travel through the head to the sensor and an amplified signal is gathered in a tester database as an acoustic emission. Abnormal conditions will trigger an unusual emission that is detected to trigger an alert.

System, method, and apparatus for in-situ acoustic emission monitoring of burnish heads in production during magnetic media cleaning or burnish process

A calibration method for determining the flying height of a glide slider for disk glide height testing is disclosed. The method utilizes a disk with bumps in situ on a disk glide height tester. The method automatically takes into account disk topography, mounting tolerances, and slider roll.

Glide slider fly height calibration method using disk spin down and slider dynamic scan

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Norman Chu