Particle Flow and Contamination in Slider Air Bearings for Hard Disk Drives

2003 ◽  
Vol 125 (2) ◽  
pp. 358-363 ◽  
Author(s):  
Xinjiang Shen ◽  
David B. Bogy
Keyword(s):  
Hard Disk Drives ◽  
Particle Flow ◽  
Viscous Drag ◽  
Air Bearing ◽  
Disk Drives ◽  
Air Bearings ◽  
Viscous Drag Force ◽  
Effect Of Particle Size ◽  
Pass Through ◽  
Particle Paths

For a particle entrained in an air bearing, various forces, such as the viscous drag force, Saffmann and Magnus lift forces and gravity force, will act on it. Such particles may pass through the air bearing or impact the slider or disk and then adhere to the surface or bounce off. In this paper, particle flow in an air bearing is simulated. The contamination of particles on a slider’s surface is analyzed using the assumption of adhesion upon impact. The effect of particle size and density on particle paths in the air bearing is studied. The numerical results show that particles are likely to contaminate slider surfaces in the transition regions on the rails. The density of the particles and the pitch angle of the slider are also found to strongly affect the flying path of the particles, and therefore, the accumulation of the particles on slider surfaces.

A Numerical Simulation of the Head-Disk Assembly in Magnetic Hard Disk Files: Part I—Component Models

1990 ◽  
Vol 112 (4) ◽  
pp. 593-602 ◽  
Author(s):  
O. J. Ruiz ◽  
D. B. Bogy
Keyword(s):  
Numerical Simulation ◽  
Natural Frequencies ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Coupled System ◽  
Air Bearing ◽  
Disk Drives ◽  
Air Bearings ◽  
Magnetic Hard Disk ◽  
Component Models

In previous papers the dynamics of air bearing sliders used to carry the read/write transducers in magnetic hard disk files has been studied. These studies are useful in evaluating the steady flying and stability of sliders subjected to various disturbances. They are particularly useful in finding the natural frequencies of the air bearings. However, in hard disk drives the sliders are attached to suspensions, which are highly specialized structures that connect the sliders to the positioning actuators. These suspensions have to be relatively stiff in lateral translation, but very flexible in pitch and roll. This latter feature is accomplished by the gimbal or flexure that connects the slider to the end of the suspension. The suspension-gimbal structure has its own natural frequencies, which can be excited by disturbances such as track seeking and impacting the actuator against the crash stop. In order to study the effect of these structures on the head-disk spacing it is necessary to include them in the numerical simulator. In this two part study such a simulator is developed. In Part I the component parts and their interfaces are modeled. In Part II the numerical simulation of the coupled system is accomplished and the numerical results of several sample simulations are presented and discussed.

Experimental Evaluation of Stiffness and Damping of Slider-Air Bearings in Hard Disk Drives

1999 ◽  
Vol 121 (1) ◽  
pp. 102-107 ◽  
Author(s):  
Q. H. Zeng ◽  
D. B. Bogy
Keyword(s):  
Dynamic Characteristics ◽  
Dynamic Properties ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Air Bearing ◽  
Disk Drives ◽  
Air Bearings ◽  
Transient Responses ◽  
Load Beam ◽  
Stiffness And Damping

The system identification method was applied to experimentally investigate the dynamic characteristics of slider-air bearings in hard disk drives. The transient responses of sliders were measured, and the modal frequencies and damping ratios that are directly related to the stiffness and damping of the bearings were obtained by data processing and parameter identification. The dynamic property of a particular advanced air bearing (AAB) slider was measured and compared with simulation results. It was found that, contrary to usual perception, the suspension assembly significantly affects the dynamic characteristics of the air bearings. Contacts between the load beam and the flexure may introduce a larger damping and nonlinear property. The preliminary results also show that the proposed method is robust for experimentally evaluating the dynamic properties of slider-air bearings.

Air Bearing Slider Simulation and Modeling for Hard Disk Drives with Ultra-Low Flying Heights

2007 ◽  
pp. 314-314
Author(s):  
B. J. Shi ◽  
D. W. Shu ◽  
B. Gu ◽  
M. R. Parlapalli ◽  
C. N. Delia ◽  
...  
Keyword(s):  
Hard Disk Drives ◽  
Hard Disk ◽  
Air Bearing ◽  
Disk Drives ◽  
Simulation And Modeling ◽  
Air Bearing Slider

Design and Dynamics of Flying Height Control Slider With Piezoelectric Nanoactuator in Hard Disk Drives

2006 ◽  
Vol 129 (1) ◽  
pp. 161-170 ◽  
Author(s):  
Jia-Yang Juang ◽  
David B. Bogy ◽  
C. Singh Bhatia
Keyword(s):  
Numerical Study ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Areal Density ◽  
Flying Height ◽  
Air Bearing ◽  
Disk Drives ◽  
Adhesion Forces ◽  
Surface Design ◽  
Ultrahigh Density

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.

Boundary Effect on Particle Motion in the Head Disk Interface

2007 ◽  
Author(s):  
Nan Liu ◽  
David B. Bogy
Keyword(s):  
Drag Force ◽  
Particle Motion ◽  
Boundary Effect ◽  
Hard Disk Drives ◽  
Areal Density ◽  
Air Bearing ◽  
Disk Drives ◽  
Head Disk Interface ◽  
Bearing Surface ◽  
Disk Interface

Simulation of particle motion in the Head Disk Interface (HDI) helps to understand the contamination process on a slider, which is critical for achieving higher areal density of hard disk drives. In this study, the boundary effect—the presence of the slider and disk—on particle motion in the HDI is investigated. A correction factor to account for this effect is incorporated into the drag force formula for particles in a flow. A contamination criterion is provided to determine when a particle will contaminate a slider. The contamination profile on a specific Air Bearing Surface is obtained, which compares well with experiments.

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