ABS Lubrication Control Trenches for Hard Disk Drive Reliability
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Solution Overview
Problem
Hard disk drives face reliability issues due to lubrication contamination, which causes air flow disruption, increased fly height, and potential head-media contact, leading to reduced signal-to-noise ratios and drive failure, especially at ultra-low fly heights.
Innovation Solution
The design of an air bearing surface (ABS) with recesses, such as trenches, on the head slider to reduce air stagnation and store lubrication, preventing its buildup near the trailing edge and maintaining optimal positioning relative to the disk surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the head is positioned closer to the media surface to increase storage capacity, then the amount of data stored on each disk surface increases, but the risk of head-media contact and lubrication contamination increases
Solution Approach 1:
The air bearing surface is segmented into functional zones using recesses and trenches that divide the surface into lubrication collection areas and clean flying areas. This segmentation allows the head to maintain ultra-low fly height for high storage capacity while preventing lubrication contamination from reaching the critical read/write elements.
Solution Approach 2:
Recesses and trenches act as intermediary structures between the media surface and the head components. These features capture and contain lubrication before it can migrate to critical areas, serving as a protective intermediary that enables ultra-low fly height operation without direct head-media contact.
2Reliability
If lubrication is allowed to migrate on the air bearing surface, then the head may be protected from direct contact, but air flow disruption occurs causing increased fly height and potential head-media contact
Solution Approach 1:
Different regions of the air bearing surface are given different properties: recesses and trenches are designed with specific depths and patterns to capture lubrication locally, while the surrounding flying surfaces maintain optimal air flow characteristics. This local differentiation allows lubrication management without compromising overall air bearing performance.
Solution Approach 2:
The air bearing surface geometry is modified by introducing recesses with specific depth parameters (e.g., 0.5-5.0 micrometers) and pattern configurations. These parameter changes create controlled lubrication traps that prevent air flow disruption while maintaining the protective lubrication layer where needed.
3Reliability
If recesses are added to the air bearing surface to control lubrication, then lubrication migration is reduced, but the device complexity increases
Solution Approach 1:
Rather than adding complex lateral structures, the solution introduces depth as a new dimension to the air bearing surface design. Recesses and trenches utilize the vertical dimension to capture and contain lubrication, providing effective lubrication control with relatively simple planar geometries that are easy to manufacture.
Solution Approach 2:
The air bearing surface is designed with a pattern of recesses that create a controlled porous-like structure. This patterned geometry allows the surface to interact with lubrication in specific ways - capturing it in recesses while maintaining air flow through the patterned openings - without requiring complex three-dimensional structures.
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 ABS recesses effectively trap excess lubrication, reducing fouling, head-disk contact, and signal distortion, thereby enhancing the reliability and performance of hard disk drives by maintaining consistent fly height and signal quality.
Implementation Method 1
reducing air stagnation on the ABS
Implementation Method 2
storing lubrication
Implementation Method 3
trap excess lubrication
Implementation Method 4
generate regions of increased air pressure in between the ABS and media surface that forces the head away from direct contact
Implementation Method 5
The disk has lubrication thereon
Data Source
AI summary
A method and apparatus for controlling lubrication in hard disk drives. Hard disk drives often include lubrication on the disks to protect the disks from incidental contact with the head slider. Embodiments of the invention include lubrication control recesses on the air bearing surface (ABS) of the head slider. The recesses reduce air stagnation on the ABS and/or store excess lubrication that migrates from the disk to the head slider. By reducing build-up of lubrication and storing excess lubrication, the lubrication control recesses avoid failure that may occur as a result of the lubrication interfering with the ABS or the read/write elements of the head.