Magnetic Disk Burnishing with Flush Alignment and Lubrication

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Solution Overview

Problem

The existing burnishing methods for magnetic disks suffer from surface contamination due to falling-off or crushing of abrasive grains from the polishing tape, which hinders the reduction of magnetic head flying height and affects the smoothness of the disk surface.

Innovation Solution

A burnishing method and apparatus that involves an alignment process to ensure the outer peripheral plate and magnetic disk surfaces are flush, preventing strong force application on the polishing tape and thereby reducing abrasive grain fallout, using a polishing tape with a liquid lubrication layer to stabilize shear forces and prevent contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If burnishing is performed to reduce magnetic head flying height, then surface smoothness is improved, but surface contamination occurs due to abrasive grain fallout

Engineering Contradiction:

Improvesurface smoothnessVSAvoidsurface contamination

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The polishing tape is pre-assembled with a liquid lubrication layer applied to its back surface before the burnishing process. This preliminary preparation ensures that the lubrication layer is already in place to reduce shear forces and prevent abrasive grain fallout during the actual burnishing operation, thereby improving surface smoothness without causing contamination.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A liquid lubrication layer is introduced as an intermediary substance between the polishing tape and the magnetic disk surface. This lubrication layer reduces the shear force during burnishing, preventing abrasive grains from falling off or crushing, thus eliminating surface contamination while maintaining the surface smoothness improvement.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If the outer peripheral plate surface is not aligned with the magnetic disk surface, then the burnishing process is simpler, but strong force is applied to the polishing tape causing abrasive grain fallout

Engineering Contradiction:

Improveburnishing process simplicityVSAvoidabrasive grain fallout

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The liquid lubrication layer is applied to the back surface of the polishing tape in advance, before the burnishing process begins. This preliminary action reduces the shear force generated during burnishing, preventing abrasive grains from falling off or crushing even when the outer peripheral plate surface is not perfectly aligned with the magnetic disk surface, thus maintaining process simplicity while preventing contamination.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If a polishing tape without liquid lubrication layer is used, then the tape structure is simpler, but shear force is not stabilized leading to abrasive grain crushing

Engineering Contradiction:

Improvepolishing tape structureVSAvoidshear force stability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The physical and chemical parameters of the polishing tape are modified by applying a liquid lubrication layer to its back surface. This changes the friction and shear force characteristics of the tape, stabilizing the shear force during burnishing and preventing abrasive grain crushing, while adding only a thin lubrication layer rather than fundamentally redesigning the tape structure.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method effectively suppresses contamination and enhances the smoothness of the magnetic disk surface, allowing for a lower magnetic head flying height and improved yield in the burnishing process.

Implementation Method 1

using a polishing tape with a liquid lubrication layer to stabilize shear forces and prevent contamination

Methodology Applied

Scientific EffectLubrication: Lubrication

Implementation Method 2

burnishing (polishing treatment) to remove minute dust or projections formed on or stuck to the surface of the magnetic disk

Methodology Applied

Scientific EffectAbrasion: Abrasion

Data Source

PatentUS9156128B2Burnishing method and burnishing apparatus

Publication Date: 2015.10.13 RESONAC HARD DISK CORP

AI summary

An object is to provide a burnishing method in which it is possible to reduce the flying height of a magnetic head by improving the smoothness of the surface of a magnetic disk while suppressing contamination of the magnetic disk due to falling-off or crushing of abrasive grains from a polishing tape.In the burnishing method, an alignment process of adjusting the position in a thickness direction of a magnetic disk 10 of an outer peripheral plate 75 installed outside an outer peripheral end 10c of at least one of the magnetic disk 10 and the magnetic disk 10 so as to make the surface of the outer peripheral plate 75 and the surface of the magnetic disk 10 become flush with each other is performed between a substrate installation process and a burnishing process.