Predicting Air Bearing Contamination Using Air Flow Pattern Analysis

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
Shuyu Zhang ◽  
Brian D. Strom
Keyword(s):  
Mathematical Model ◽  
Flow Pattern ◽  
Pattern Analysis ◽  
Liquid Droplet ◽  
Disk Surface ◽  
Two Dimensions ◽  
Air Bearing ◽  
Vertical Flow ◽  
Disk Drives ◽  
Bearing Surface

A new method is introduced for predicting particle and liquid droplet contamination on an air bearing surface. The method primarily relies on the analysis of flow patterns nearest the air bearing surface, restricted to two dimensions. In addition, a mathematical model for the vertical flow perpendicular to the disk surface adds clarity to the contamination mechanisms. The predictions compare well with contamination patterns observed in prototype disk drives.

Study of air bearing with grooved disk surface in near-field optical disk drives

2005 ◽  
Vol 41 (2) ◽  
pp. 1047-1049 ◽  
Author(s):  
H.C. Wang ◽  
T.S. Liu ◽  
C.S. Chang
Keyword(s):  
Near Field ◽  
Disk Surface ◽  
Optical Disk ◽  
Air Bearing ◽  
Disk Drives

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.

Pumping Effect of Slider Air Bearing Surface for Non-Langmuir Adsorption

2010 ◽  
Author(s):  
Bo Zhang ◽  
Akira Nakajima
Keyword(s):  
Disk Surface ◽  
Air Bearing ◽  
Head Disk Interface ◽  
Bearing Surface ◽  
Adsorption Model ◽  
Adsorbed Film ◽  
Disk Interface ◽  
Langmuir Adsorption ◽  
Langmuir Adsorption Model ◽  
Slider Air Bearing

Numerical analysis of the adsorbed film thickness at the air bearing surface is conducted using the non-Langmuir adsorption model. It is found that the adsorbed film at the air bearing surface becomes significant when the viscosity of adsorbed film is higher than about 1 Pa s. The adsorbed contaminant will accumulate at the rear end of the slider, and it is possible that the accumulated liquid-like contaminant may form a liquid tail which will directly contact with the disk surface, resulting in a crush of the head/disk interface.

Effect of Slider Burnish on Disk Damage During Dynamic Load/Unload

1998 ◽  
Vol 120 (2) ◽  
pp. 332-338 ◽  
Author(s):  
M. Suk ◽  
D. Gillis
Keyword(s):  
Contact Stress ◽  
Disk Surface ◽  
Hertzian Contact ◽  
Radius Of Curvature ◽  
Air Bearing ◽  
Head Disk Interface ◽  
Bearing Surface ◽  
Disk Interface ◽  
Current Design ◽  
Hertzian Contact Stress

Two of the most difficult issues to resolve in current design of head/disk interface in magnetic recording devices are stiction and durability problems. One method of overcoming these problems is by implementing a technology known as load/unload, where the system is designed so that the slider never touches the disk surface. One potential problem with this type of system is slider/disk contact induced disk defects. The objective of this paper is to show that the likelihood of disk scratches caused by head/disk contacts during the load/unload process can be significantly decreased by rounding the edges of the air-bearing surface. Using the resistance method, we observe that head/disk contacts burnish the corners of the slider and thereby decrease exponentially with load/unload cycles. A well burnished slider rarely causes any disk damage thus resulting in an interface with significantly higher reliability. A simple Hertzian contact stress analysis indicates that the contact stress at the head/disk interface can be greatly decreased by increasing the radius of curvature of the air-bearing surface edges.

Meniscus Adhesion at Ultra-Low Flying Slider-Disk Interfaces

2005 ◽  
Author(s):  
C. Mathew Mate ◽  
Robert N. Payne ◽  
Peter Baumgart ◽  
Kathy Kuboi
Keyword(s):  
Experimental Evidence ◽  
Van Der Waals ◽  
Adhesive Force ◽  
Air Bearing ◽  
Disk Drives ◽  
Bearing Surface ◽  
Slider Air Bearing ◽  
Adhesive Forces

As head-disk spacings in disk drives approach a few nanometers, adhesive forces between the slider and disk can drastically alter the slider flying dynamics. At these small separations, it is still unclear, however, what type of adhesive force dominates. Most previous studies have concentrated on van der Waals and electrostatic attractive forces [1], which are readily incorporated into air bearing simulations. In this talk, we provide experimental evidence that the dominant adhesive force originates from menisci forming around the low flying portions of the slider air-bearing-surface as the spacing transitions from near-contact to contact.

Optimization of Proximity Recording Air Bearing Sliders in Magnetic Hard Disk Drives

1999 ◽  
Vol 122 (1) ◽  
pp. 257-259 ◽  
Author(s):  
Matthew A. O’Hara ◽  
Yong Hu ◽  
David B. Bogy
Keyword(s):  
Numerical Optimization ◽  
Tribological Behavior ◽  
Contact Stiffness ◽  
Hard Disk Drives ◽  
Tribological Performance ◽  
Air Bearing ◽  
Disk Drives ◽  
Bearing Surface ◽  
Magnetic Hard Disk ◽  
Made In

The object of this paper will be to optimize the contact stiffness (CS) of an existing proximity recording air bearing surface (ABS). The CS is a measure of the slider’s increase in contact force with increase in slider/disk interference. By minimizing this, the amount of force transmitted through the slider at the interface is minimized. This should, in turn, minimize the amount of wear, improving the tribological performance. Comparisons of the pre- and post-optimized slider have been made. In combination with research that demonstrates the ability of the CS parameter to predict tribological behavior (Hu et al., ASME J. Tribol., 120, pp. 272–279) this paper demonstrates the feasibility of numerical optimization of the tribological behavior of proximity recording air bearing sliders. [S0742-4787(00)03201-X]

Accumulation Process of Liquid-Like Chemicals on the Air Bearing Surface of a Slider in Hard Disk Drives

2005 ◽  
Author(s):  
Bo Zhang ◽  
Akira Nakajima
Keyword(s):  
Film Thickness ◽  
Accumulation Rate ◽  
Hard Disk Drives ◽  
Numerical Results ◽  
Air Bearing ◽  
Disk Drives ◽  
Accumulation Process ◽  
Bearing Surface ◽  
Adsorbed Film ◽  
Inner Surface

The pumping effect which is proposed by the authors to explain the accumulation of liquid-like chemicals on the air bearing surface has been analyzed by taking into the account the incline of the air bearing surface. Numerical results show that the accumulation rate of the contaminant decreases as the incline of the air bearing surface increases and at the same time the maximum adsorbed film thickness shifts from the outlet to the inner surface.

Parameter Effects on Thermal Protrusions of Magnetic Head Sliders

2005 ◽  
Author(s):  
M. Kurita ◽  
J. Xu
Keyword(s):  
Heat Transfer ◽  
Hard Disk Drives ◽  
Flying Height ◽  
Parameter Study ◽  
Air Bearing ◽  
Disk Drives ◽  
Magnetic Head ◽  
Bearing Surface ◽  
Simulated Temperature ◽  
Height Change

The heat transfer in the magnetic head sliders in hard disk drives, the thermal protrusion (TPR) of the head elements, and the flying height change of such sliders were numerically simulated. A simulated temperature distribution of the air-bearing surface correlated well with our experimental results. A parameter study showed that decreasing the thickness of the alumina base coat or increasing the size of the pole and shields of the head elements can reduce the magnitude of write-current-induced protrusion (W-TPR). However, a longer pole and shields increase ambient-temperature-induced protrusion (T-TPR). For W-TPR, the reduced flying height of the slider is partly compensated for by increased air pressure on the air-bearing surface. However, almost the entire magnitude of T-PTR translates into a reduction in flying height.

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