Slider Air-Bearing Surface Efficiency-Flattening Hole Design
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Solution Overview
Problem
Existing magnetic storage systems face challenges with slider designs that result in unstable fly height, lubricant pickup, and insufficient stiffness, leading to poor magnetic interfacing and potential catastrophic failures due to high peak pressures and mid-disk hump phenomena.
Innovation Solution
The introduction of an efficiency-flattening hole (EFH) in the trailing-edge pad of the slider, which redirects airflow uniformly over the magnetic head, reducing touch-down power hump and improving thermal fly-height control, thereby stabilizing the fly height and reducing lubricant pickup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional slider designs are used, then the structure is simple, but the fly height becomes unstable and lubricant pickup occurs due to high peak pressures
Solution Approach 1:
The trailing edge pad is segmented into multiple levels (first level at 0 nm, second level at 100-200 nm below, third level at 300-2000 nm below) to create the efficiency-flattening hole. This segmentation allows different regions to serve different functions: the first level provides the primary air-bearing surface, the second level redirects airflow to reduce peak pressures, and the third level further stabilizes airflow, collectively improving fly height stability without requiring complete redesign of the slider structure.
Solution Approach 2:
The efficiency-flattening hole is implemented as a localized feature within the trailing edge pad rather than modifying the entire slider. The hole creates localized airflow redirection at specific positions (second and third levels below the first level) to address peak pressure issues only where they occur, while maintaining the simplicity of the overall slider structure and other functional areas.
2Reliability
If conventional air-bearing surfaces are used, then the design is simple, but mid-disk hump phenomena occur causing poor magnetic interfacing
Solution Approach 1:
The air-bearing surface is segmented by creating the efficiency-flattening hole with multiple distinct levels (first, second, and third levels) in the trailing edge pad. This segmentation allows the surface to control airflow at different heights, effectively mitigating the mid-disk hump phenomenon and improving magnetic interfacing quality without requiring complete redesign of the air-bearing surface geometry.
Solution Approach 2:
The efficiency-flattening hole acts as an intermediary structure that modifies airflow patterns between the disk surface and the slider. By introducing this intermediate feature with multiple levels, the patent controls the air bearing pressure distribution, eliminating mid-disk hump and ensuring consistent magnetic interfacing across the disk surface.
3Power
If traditional trailing edge pads are used, then manufacturing is simple, but touch-down power hump and re-coil effects increase
Solution Approach 1:
The trailing edge pad is divided into multiple manufacturable levels (first level at 0 nm, second level at 100-200 nm below, third level at 300-2000 nm below) to create the efficiency-flattening hole. This segmentation enables the complex airflow control feature to be fabricated using standard semiconductor manufacturing techniques, balancing improved touch-down power profile with manufacturing feasibility.
Solution Approach 2:
The invention changes the geometric parameters of the trailing edge pad by introducing the efficiency-flattening hole with specific depth ranges (second level 100-200 nm below first level, third level 300-2000 nm below second level). These parameter changes optimize the airflow characteristics to reduce touch-down power hump and re-coil effects while remaining within standard manufacturing capabilities.
4Force
If high peak pressures are generated, then air-bearing force is sufficient, but lubricant pickup and plastic deformation occur
Solution Approach 1:
The efficiency-flattening hole creates localized airflow modification at the trailing edge pad, specifically at the second and third levels. This local quality change redirects airflow to distribute pressure more evenly, maintaining sufficient air-bearing force while reducing peak pressures that cause lubricant pickup and plastic deformation in other regions.
Solution Approach 2:
The efficiency-flattening hole serves as an intermediary airflow control structure that mediates between the disk surface and the slider body. It redistributes the air bearing pressure to maintain overall force while eliminating localized high-pressure zones that lead to harmful lubricant pickup and material deformation.
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 EFH design achieves a nearly flat touch-down power profile, enhances pull-back efficiency, minimizes re-coil effects, and reduces plastic deformation, resulting in improved areal density capacity and reliability with reduced risk of fencing and operational complexity.
Implementation Method 1
The slider rides on a cushion or bearing of air created above the surface of the disk as the disk rotates at its operating speed. The ABS is designed to generate an air-bearing force that counteracts a preload bias that pushes the slider toward the disk.
Data Source
AI summary
Disclosed herein are hard disk drive sliders having an air-bearing surface (ABS) with an efficiency-flattening hole (EFH). The sliders comprise a trailing edge pad that has a first surface at a first level with a first perimeter, a second surface at a second level, the second level being below the first level, the second surface being substantially parallel to the first surface, the second surface having a second perimeter, wherein the second perimeter is within the first perimeter, and a third surface at a third level, the third level being below the second level, the third surface being substantially parallel to the first and second surfaces, the third surface having a third perimeter, wherein the third perimeter is within the second perimeter.