Effects of Surface Roughness on Static Characteristics of Air Bearing Films in Hard Disk Drives with Ultra-low Flying Heights

To achieve the areal density goal in hard disk drives of 1Tbit∕in.2 the minimum physical spacing or flying height (FH) between the read/write element and disk must be reduced to ∼2nm. A brief review of several FH adjustment schemes is first presented and discussed. Previous research showed that the actuation efficiency (defined as the ratio of the FH reduction to the stroke) was low due to the significant air bearing coupling. In this paper, an air bearing surface design, Slider B, for a FH control slider with a piezoelectric nanoactuator is proposed to achieve virtually 100% efficiency and to increase dynamics stability by minimizing the nanoscale adhesion forces. A numerical study was conducted to investigate both the static and dynamic performances of the Slider B, such as uniformity of gap FH with near-zero roll over the entire disk, ultrahigh roll stiffness and damping, low nanoscale adhesion forces, uniform FH track-seeking motion, dynamic load/unload, and FH modulation. Slider B was found to exhibit an overall enhancement in performance, stability, and reliability in ultrahigh density magnetic recording.

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Local Adaptive Multi-Grid Control Volume Method for the Air Bearing Problem in Hard Disk Drives

ASME/STLE 2012 International Joint Tribology Conference ◽

10.1115/ijtc2012-61118 ◽

2012 ◽

Author(s):

Liping Li ◽

David B. Bogy

Keyword(s):

Control Volume ◽

Hard Disk Drives ◽

Hard Disk ◽

Adaptive Grid ◽

Air Bearing ◽

Disk Drives ◽

Control Volume Method ◽

Generating Method ◽

The Stability ◽

Volume Method

A new local adaptive grid-generating algorithm is developed and integrated with the multi-grid control volume method to simulate the steady state flying condition of air bearing sliders in HDDs (Hard Disk Drives) accurately and efficiently. Two sliders are used to demonstrate the applicability of this method. The results show that this new local adaptive grid-generating method improves substantially the stability and efficiency of the simulation scheme.

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Dynamics of air bearing sliders flying on partially planarized bit patterned media in hard disk drives

Microsystem Technologies ◽

10.1007/s00542-010-1191-9 ◽

2011 ◽

Vol 17 (5-7) ◽

pp. 805-812 ◽

Cited By ~ 13

Author(s):

Liping Li ◽

David B. Bogy

Keyword(s):

Hard Disk Drives ◽

Hard Disk ◽

Air Bearing ◽

Disk Drives ◽

Bit Patterned Media ◽

Patterned Media

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An Efficient FE Analysis for Complex Low Flying Air-Bearing Slider Designs in Hard Disk Drives—Part I: Static Solution

Journal of Tribology ◽

10.1115/1.3140606 ◽

2009 ◽

Vol 131 (3) ◽

Cited By ~ 2

Author(s):

Puneet Bhargava ◽

David B. Bogy

Keyword(s):

Hard Disk Drives ◽

Hard Disk ◽

Static Solution ◽

Flying Height ◽

Air Bearing ◽

Pressure Gradients ◽

Disk Drives ◽

Bearing Stiffness ◽

Novel Method ◽

Mesh Refinements

Prediction of the steady state flying height and attitude of air-bearing sliders in hard disk drives via simulations is the basis of their design process. Over the past few years air-bearing surfaces have become increasingly complex incorporating deep etches and steep wall profiles. In this paper we present a novel method of solving the inverse problem for air-bearing sliders in hard disk drives that works well for such new designs. We also present a new method for calculating the static air-bearing stiffness by solving three linear systems of equations. The formulation is implemented, and convergence studies are carried out for the method. Mesh refinements based on flux jumps and pressure gradients are found to work better than those based on other criteria.

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