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]

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.

Contact Take-Off Characteristics of Proximity Recording Air Bearing Sliders in Magnetic Hard Disk Drives

1999 ◽  
Vol 121 (4) ◽  
pp. 948-954 ◽  
Author(s):  
Yong Hu
Keyword(s):  
Hard Disk Drives ◽  
Air Bearing ◽  
Disk Drives ◽  
Head Disk Interface ◽  
Taper Angle ◽  
Wear Factor ◽  
Disk Interface ◽  
Partial Contact ◽  
Magnetic Hard Disk ◽  
Wear Law

A partial contact air bearing model and Archard’s wear law are used to investigate the air bearing and wear characteristics of proximity recording sliders during a take-off process. The air bearing pitch torque, pitch and contact force are used to characterize the contact take-off process. In addition, the wear factor derived from the Archard’s wear law is employed to measure the take-off performance. The results indicate the existence of two distinct take-off stages: a period of rapidly increasing pitch preceding a relatively steady take-off event. The proper range of taper angle and step height, which produce a rapid initial pitch increase and steady subsequent take-off as well as less wear in the head/disk interface, are determined through simulation. While the simulation results demonstrate the negligible effect of crown height on the rate of the initial pitch increase, larger crown values are shown to yield higher pitch and smaller wear in the head/disk interface during the take-off process. In summary, the partial contact air bearing simulation and the wear factor calculation of the take-off process, developed in this study, offers a fast and accurate analytical tool to optimize ABS design for the fast take-off performance.

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.

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.

Some Advanced Air-Bearing Design Issues for Proximity Recording

1998 ◽  
Vol 120 (3) ◽  
pp. 566-570 ◽  
Author(s):  
David B. Bogy ◽  
Sha Lu ◽  
Matthew A. O’Hara ◽  
Shuyu Zhang
Keyword(s):  
Hard Disk Drives ◽  
Accelerate Particle ◽  
Air Bearing ◽  
Disk Drives ◽  
Design Issues ◽  
Particle Accumulation ◽  
Interface Phenomena ◽  
Trailing Edges ◽  
Bearing Design ◽  
Magnetic Hard Disk

In magnetic hard disk drives the minimum spacing between the air-bearing slider and disk has been reduced to under 50 nm, and some drives now employ so-called proximity sliders that are designed to operate at some level of interference between the slider and the peak asperities on the disk. This ultra-low flying condition brings into play some new interface phenomena and accentuates some of the well known ones as well. In this paper, we consider some air-bearing design issues related to proximity recording. First, we examine the effects of shear flow in the bearing, which is usually neglected, and we show that for high-pitch proximity slider designs the effect is not negligible. Next, we note that such low spacing also tends to accelerate particle accumulation at the trailing edges of the slider. In an effort to address this problem, a model is developed for calculating forces on particles in the air bearing. Including this in the CML air bearing design code we show that designs can be created that eject most of the particles from the sides rather than trapping them at the trailing edge. Finally, we investigate the performance of proximity sliders with regard to their sensitivity to altitude changes. We include altitude sensitivity as an objective in the design optimization scheme and demonstrate that it can yield air-bearing design with performance much less sensitive to changes in altitude.

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
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