International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Dennis Leonard Fox

James Aloysius Hagan

Douglas Howard Piltingsrud

Steven F Starcke

John C Shen

Brent Ray Den Hartog

Kannimangalam Venkatasubramanyam Viswanathan

Karl Robert Erickson

Frederick Paul Benning

John Patrick Hagen

Janice Blue Ostrom

Bradley J Offuh

Theresa Marie Lewis

R Paul Thicke

David M Nordyke

Thomas E Folkert

Stanley B O'Brien

Ricky P Thicke

Bruce R Diemer

Douglas Allen Kuchta

Donald L Mabe

Paul Henry Hanson

Kerry R Lindemann

The present invention utilizes a combination of chemical and mechanical finishing processes to polish a disk substrate surface to near atomic smoothness. Broadly speaking, the surface of a disk substrate that has been machined (i.e., rough ground) to a predetermined surface roughness is subjected to attack by a chemical formulation (called an attacking agent). The chemical formulation is used to soften the substrate material. Then, the softened material is &ldquo;wiped away&rdquo; via mechanical action.

Substrate independent superpolishing process and slurry

A fluid jet cutting method and apparatus for cutting an object from a sheet. In one embodiment, a fluid jet stream is directed against a glass sheet to cut an annular disk substrate for use in a data storage device. The sheet is supported by first, second and third support members. The support surfaces of the second and third support members are respectively positioned inside central openings in the first and second support members. A vacuum pulls the sheet against the support surface of at least the second support member. Preferably, plural central openings in the first support member accommodate plural second and third support members, whereby plural substrates are cut from the sheet. The sheet preferably includes plural layers removably adhered to one another, whereby plural substrates are simultaneously formed by a single fluid jet stream. A protective layer may cover at least one surface to the sheet.

Fluid jet cutting method and apparatus

An apparatus and method of reclaiming a disk substrate. The cost of reclaiming a disk substrate can be lower, and the quality higher, than making a new one from a blank. A layer of a data storage disk is stripped, e.g., by acid/oxidizing bath immersion. The stripped disk is polished in a carrier between polishing pads, with the relative velocity of the polishing pads as seen by the disk being precisely controlled so that an equal amount of stock is removed from each side. Preferably, several stripped disks are sorted into groups based on disk thickness, and disks from one of the groups are simultaneously polished in the carrier. Sorting improves stock removal uniformity from disk to disk. The polished disks are cleaned and, preferably, ordered in a cassette for stacking in a storage device based on disk thickness to more easily meet a mean center specification.

Apparatus and method for reclaiming a disk substrate for use in a data storage device

A dressing disk for dressing and reconditioning the polishing pad of a planetary disk polishing machine is fabricated by plating a nickel/diamond matrix layer onto a stainless steel disk wherein the matrix layer thickness is developed or plated to a thickness which leaves exposed about 25 percent of the fine diamond particles, thereby forming a surface that has the look and feel of medium to coarse sandpaper. The dressing disks are inserted into the holes in a disk carrier of a planetary polishing machine and driven by its central rotary drive. While being so driven under a flow of water to carry away abraded particles, a pair of polishing pads are engaged with the disk surfaces and forced together with a loading or down force to cause the disks to abrade or grind away a thin surface layer of the polishing pad, thereby removing glazing and exposing cerium particles embedded in the urethane matrix of the polishing pad to engage the glass disks to be polished to a very smooth surface for use as substrates for magnetic memory disks useable in disk drives.

Process of dressing glass disk polishing pads using diamond-coated dressing disks

The invention is a method for improving the flatness of nonmetallic substrates and preferably glass disks. The method comprises the steps of mounting the glass disk on a support. The support preferably comprises a refractory metal having a cooling rate substantially similar to the disk. The disk is then subjected to heating to a temperature in the anneal region for the given material for a period ranging from about 0.5 hours to 12 hours or longer, and then the disk is controllably cooled. The glass disk is preferably cooled at a rate of about 0.25.degree. C./minute to 1.5.degree. C./minute to room temperature. The invention also comprises a hard disk glass memory element and a data storage and retrieval device comprising this element.

Method for improving the flatness of glass disk substrates

An improved method and formulation is shown for preparing polishing media for superfinishing pure metal surfaces. A combination of hydrophobic and hydrophilic silicone surfactants is used to control the porosity and water absorption during use whereby durability is obtained and the catalyst concentration is regulated to control hardness to achieve durability without scratching the workpiece. Density is controlled by the quantity of mixture with which a closed mold is charged. To produce successful media it is also necessary to preheat the closed mold and to be certain that the resin mixture of particles, polyol and additives does not exceed 120 degrees F. prior to final mixture with isocyanate just before charging the mold and curing. Also a longer cure at a lower temperature enhances the qualities of the resulting polishing media.

Fixed abrasive polishing media

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Rochester, MN, United States of America

Dennis Leonard Fox