Hitachi Global Storage Technologies Netherlands B.v.

International Business Machines Corporation

Bradley Frederick Baumgartner

Hang Fai Ngo

Shanlin Duan

Bob Clyde Robinson

Norman Chu

Yu Lo

Patricia Galindo

Connie H Moy

Charles Chung Lee

Yan Liu

James Hammond Brannon

Li Tang

Tony Mello

Christopher Ramm

Elmer Tyree York

Nalin Zhou

Jorge Daniel Colonia

Parul Agrawal

Ka Chi Wong

Erich Chuh

Alma Lujan Ortega-Avery

Andrew John Buhler

Song How Wong-Jessel

An-Chou Andrew Chen

Roger Yu Lo

Huyen D Do

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

A disk for calibrating glide heads utilizes a dual-zone configuration of multiple laser melt bumps having selected heights. Averaging the PZT response over many bumps significantly narrows the response distribution, resulting in greater certainty and correlation of the PZT amplitude to bump height. The multiple calibration bumps are circumferentially arranged on a disk surface at a selected radius in a ring-like manner. A second head cleaning zone is provided near the inner diameter of the disk to provide for increased reproducibility of the PZT calibration response. The second zone is densely textured and serves to clean the glide head prior to its use in the calibration zone.

Apparatus and method for glide height calibration of disk surfaces by use of dual-zone laser texture

An apparatus and method for detecting and marking delamination defects on thin film disks are disclosed. The apparatus includes a read/write (R/W) head and a burnishing head mounted on separate arms that access the disk while spinning on the test stand. The controller uses the R/W head to perform an initial magnetic test of selected areas on the disk to establish an initial defect map. The burnish head is then flown over the surface for an extended time to accelerate and open up the latent delamination defects by impacting protruding material. The R/W head is then used to perform a second magnetic test which is compared against the first test to identify the delamination defects which have been developed by the burnishing. The delamination defects are then marked with a magnetic pattern which aids in optically locating the defect during subsequent failure analysis.

Thin film delamination detection for magnetic disks

A disk for a disk drive uses a circular platter having first and second sides and a circumferential edge. The circumferential edge of the disk has four symmetrically spaced apart shadows and a fifth or additional shadow that gives the disk an asymmetrical shadow signature. The fifth shadow is offset relative to the other shadows, which have congruent arcuate lengths and separation. The fifth shadow has an arcuate length that is about half as long as those of the other shadows, and is closely spaced adjacent to one of the other shadows. The asymmetric shadow signatures of the disk is used to precisely determine both the circumferential position of the platters and their planar orientation (i.e., A-side or B-side). For example, when the disk is mounted on a tool spindle and rotated, an optical detector detects the pattern of the shadows and feeds the data to a computer system. The rotational position of the spindle also is relayed to the computer for coordinating the processing of the rotating disk. When the disk is mounted on a different tool, the same shadow signature is used to determine its planar and angular positions.

Disk drive platter using sputter shadows thereon for determining orientation thereof

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Los Banos, CA, United States of America

Bradley Frederick Baumgartner