A New Universal Approach for Slider Optimization

2002 ◽  
Author(s):  
Andreas V. Hanke ◽  
Frank E. Talke
Keyword(s):  
Objective Function ◽  
The Other ◽  
Flying Height ◽  
Air Bearing ◽  
Disk Drives ◽  
Bearing Surface ◽  
New Approach ◽  
Universal Approach ◽  
The Individual ◽  
Optimum Solution

A new method for the optimization of slider bearings in magnetic recording disk drives is described. The new approach subdivides the chosen design area of the slider to be optimized in a number of small rectangular subregions. Each subregion is allowed to be at one of two height levels, one level corresponding to the air bearing surface and the other to the intermediate level between recess level and air bearing level. The pressure distribution over the slider and the flying height of the slider are calculated for all possible combinations of height levels of the subregions and the solution is determined that minimizes a chosen objective function. After determining an optimum solution with an initial coarse subdivision, a refinement of the solution is obtained by further subdivision of the individual subregions, and repeating the evaluation of the objective function to determine the optimum solution. The subregion approach does not require an a priory knowledge of a good initial design and results in novel air bearing contours.

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.

The Influence of Air-Bearing Surface Geometry on the Dynamics of Sliders

1992 ◽  
Vol 114 (1) ◽  
pp. 26-31 ◽  
Author(s):  
M. Suk ◽  
T. Ishii ◽  
D. Bogy
Keyword(s):  
Surface Defect ◽  
Laser Interferometer ◽  
Low Frequency ◽  
Frequency Component ◽  
Flying Height ◽  
Disk Drives ◽  
Bearing Surface ◽  
Surface Geometry ◽  
Spacing Variation ◽  
Slider Motion

We investigate the influence of crown on slider dynamics during the takeoff stages of disk drives using the multi-channel laser interferometer. We show that a two-dimensional analysis of slider dynamics during takeoff/landing cannot explain all the observed phenomena. We also examine the crown effect on slider motion while it is flying on a thin film disk with a crater-like surface defect. Finally, we measure the spacing variation of the slider as a function of disk speed. It is observed that the initial motion of negative crown sliders during takeoff can be quite similar to positive crown sliders, although the process is quite different. Furthermore, the results suggest that the negative crown sliders may lead to more disk wear due to longer sliding distances. We observed that during steady flying conditions the craterlike surface defect on the disk produced significantly larger motions for negative crown sliders than positive crown sliders. Lastly, we found that both the waveform and magnitude of the low frequency component of the spacing fluctuation is independent of the slider flying height.

Modeling and Simulation of Holonic Meta-Algorithm in Scheduling Process Using PERT Technique − Optimization in Job Shop Scheduling Problem

2015 ◽  
Vol 760 ◽  
pp. 199-204
Author(s):  
Mircea Gorgoi ◽  
Corneliu Neagu
Keyword(s):  
Objective Function ◽  
Job Shop ◽  
Job Shop Scheduling ◽  
Scheduling Problem ◽  
Job Shop Scheduling Problem ◽  
New Approach ◽  
Shop Scheduling ◽  
Technique Optimization ◽  
Optimum Solution

In generally scheduling can be viewed as optimization, bound by sequence and resource constrain and the minimization of the makespan is often used as the criterion. In this paper minimization of the makespan or complete time will be used such as an objective function and not the criterion of the decision. The new approach use heuristic elementary priority dispatch rules as the criterion of the decision. This research purpose a new methodology which use a specific elements of PERT techniques to find the optimum solution. New approach establish a solution's space where are find the all solution of the problem. Determination of the solution's space is realized by a meta-algorithm which take in account all the variant of the solutions of the process.

An Optimization Method for Design of Subambient Pressure Shaped Rail Sliders

1999 ◽  
Vol 121 (3) ◽  
pp. 575-580 ◽  
Author(s):  
Dong-Hoon Choi ◽  
Tae-Sik Kang
Keyword(s):  
Design Methodology ◽  
Optimization Method ◽  
Flying Height ◽  
Air Bearing ◽  
Bearing Surface ◽  
Programming Technique ◽  
Design Synthesis ◽  
Method Of Feasible Directions ◽  
Design Variables ◽  
Simulation Results

This study proposes a design methodology for determining configurations of subamient pressure shaped rail sliders by using a nonlinear programming technique in order to meet the desired flying characteristics over the entire recording band. The desired flying characteristics considered in this study are to minimize the variation in flying height from a target value, to keep the pitch angle within a suitable range, and to ensure that the outside rail flies lower than the inside rail even with the roll distribution due to manufacturing process. The design variables selected are recess depth, geometry of the air bearing surface, and pivot location in the transverse direction of the slider. The method of feasible directions in Automated Design Synthesis (ADS) is utilized to automatically find the optimum design variables which simultaneously meet all the desired flying characteristics. To validate the suggested design methodology, a computer program is developed and applied to a 30 percent/15 nm twin rail slider and a 30 percent/15 nm tri-rail slider. Simulation results for both sliders demonstrated the effectiveness of the proposed design methodology by showing that the flying characteristics of the optimally designed sliders are enhanced in comparison with those of the initial ones.

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.

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.

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.

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

2009 ◽  
Vol 131 (3) ◽  
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.

Effect of Ultra-Thin Liquid Lubricant Films on Dynamics of Nano-Spacing Flying Head Sliders in Hard Disk Drives

2004 ◽  
Vol 126 (3) ◽  
pp. 565-572 ◽  
Author(s):  
Norio Tagawa ◽  
Noritaka Yoshioka ◽  
Atsunobu Mori
Keyword(s):  
Film Thickness ◽  
Hard Disk Drives ◽  
Lubricant Film ◽  
Flying Height ◽  
Air Bearing ◽  
Disk Drives ◽  
Lubricant Film Thickness ◽  
Liquid Lubricant ◽  
Lubricant Films ◽  
Bearing Dynamics

This paper describes the effect of ultra-thin liquid lubricant films on air bearing dynamics and flyability of nano-spacing flying head sliders in hard disk drives. The dynamics of a slider was monitored using Acoustic Emission (AE) and Laser Doppler Vibrometer (LDV). The disks with lubricant on one half of disk surface thicker than the other half as well as with uniform thickness lubricant were used to investigate the interactions between the slider and lubricant film experimentally. As a result, it was found that the flying height at which the slider-lubricant contact occurs depends on the lubricant film thickness and it increases as the lubricant film thickness increases. Its flying height is also dependent on the mobile lubricant film thickness under the condition that the total lubricant film thicknesses are the same and the lubricant bonded ratios are different. It increases as the mobile lubricant film thickness increases. The slider-lubricant contact flying height based on the theory for capillary waves is in good agreement with the experimental results. Regard to air bearing dynamics due to the slider-lubricant interactions, it also depends on the mobile lubricant thickness as well as the total lubricant film thickness. However, we should carry out more experimental and theoretical studies in order to confirm and verify these experimental results. In addition, the effect of nonuniform lubricant film thickness on head/disk interface dynamics has been studied. It was found that the lubricant film thickness nonuniformity caused by the slider-lubricant interactions could be observed.

Flying Clearance Distribution With Thermal Flying Height Control in Hard Disk Drives

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Sung-Chang Lee ◽  
George W. Tyndall ◽  
Mike Suk
Keyword(s):  
Temperature Compensation ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Flying Height ◽  
Disk Drives ◽  
Disk Interface ◽  
Height Control ◽  
Thermal Flying Height Control ◽  
Height Change ◽  
The Individual

Flying clearance distribution with thermal flying height control (or thermomechanical actuation) is characterized. Especially, factors contributing to variation in the flying clearance are identified based on the flying height change profiles taken from the burn-in process of hard disk drives and Gage R&R (repeatability and reproducibility) test of touch down repeatability. In addition, the effect of static temperature compensation scheme on the flying clearance distribution is investigated, and the disadvantage of static adaptation to temperature change is identified. In order to avoid early catastrophic head-disk interface failures due to poor static temperature compensation, dynamic clearance adjustment is necessary whenever environmental condition changes. Otherwise, static temperature compensation using the individual temperature sensitivity values of each head needs to be applied.

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