• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.8
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• pp.1056-1061
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• 2000

Particles existing in a hard disk drive are known as a major source of TA(thermal asperity). Researchers have investigated how particles induce the TA phenomena, but have not verified yet the reason why and how particles are generated in a HDD. The objective of this study is to investigate why and how particles are generated, and in what condition, the largest number of particles is generated. The number of particles generated in a HDD was measured over the landing zone after various rest times of slider and during various motions and positions of slider. It is found that the large number of particles was generated when the HDD was turned on after a long rest time of slider and that a few of particles were continuously generated when the slider flied over the disk surface. It is thought that the number of particles generated in a HDD was related to the rest time of slider because the rest time of slider increased stiction, and that there were intermittent contacts between the slider and the disk surface when the slider flied over the disk surface.

• KSTLE International Journal
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• v.5 no.2
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• pp.52-56
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• 2004

The hard disk drive performance depends strongly on air bearing characterisitcs of the head slider. The objective of the slider design is to provide accurate positioning of the magnetic read/write element at the very small height above the disk. Application of the numerical methods is required due to complexity of the air bearing surface of the slider. The Boundary-Fitted Coordinate System Divergence Formulation method can be used for calculation of pressure distribution in the case of steep film thickness gradients. In the present work, the interpolating functions used in the expression for the Couette flow are modified in order to improve the solution characteristics in the extremely high compressibility number region. The advantages of the modified method are demonstrated on example of the flat skewed slider. Finally, the modi.ed method is applied to analysis of the static characteristics of the femto-slider. The analysis results indicate the effect of the silder's air bearing surface crown on the flying height and the pitching angle in steady state position.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.208-213
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• 2007

Pantograph is set on the roof of Subway. This plays the role of staying proper current on Subway when Subway is running or not. Pantograph includes Slider. Slider is most important part of Pantograph because this part is used to receive current from Contact Wire by dynamic interaction with Contact Wire. In general, material of Slider is steel, copper, or carbon alloy. Especially, SEOUL METRO uses Slider of sintered cualloy, but there is problem. This Slider causes over wearing during rainy season. We should reduce wearing between Contact Wire and Slider. Reducing this wear is most valuable technology in Subway system. I performed experiments to find out the best way that reduces the wear. I can find the best way as I change the rate of the alloy.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.842-845
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• 2000

It is essential to reduce stiction between the slider and the disk for super-smooth media such as glass disk for high density recording. We developed a stiction-reduced slider by fabricating mechanical bumps on the air bearing surface of the slider by indentation technique. This paper presents a possibility and concept of Stiction-Free-Slider which can operate on the data zone of a magnetic disk. The slider hat many bumps and their heights are in the tens of nm range. The SFS shows good performance on the data zone. Moreover, little wear of the bumps was observed when the preload was small.

• KSTLE International Journal
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• v.5 no.1
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• pp.23-27
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• 2004

The object of the present work is the numerical analysis of the computer hard disk slider. The pressure between slider and disk surfaces is calculated using the Boundary Fitted Coordinate System and Divergence Formulation for the nonlinear Reynolds' equation solution. The optimization scheme is applied to search for the steady state position of the slider. The simplified method is given for the case of the fixed inclined pad. The film thickness ratios and pitching and rolling angles are considered as alternative choice of the slider's coordinates. The behavior of the objective function for the Negative Pressure slider is studied in details. Methods of conjugate directions and feasible directions are applied.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.160-165
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• 2002

The flying height of contact slider is determined by vertical and pitching motions. This paper performed the computer simulation for flying height change of contact slider. It is changed by many parameters, contact stiffness. contact damping, all bearing stiffness ratio and so on. So computer simulation analysis is performed for knowing for what change of these parameters influences in flying height of contact slider. The practical recording zone surface is gotten by using SPM. In recording zone, flying height is simulated for each parameter. the settling time which the flying height of contact slider is lower than 10nm is analyzed over practical disk surface for changing each parameter. Through these results, the contact slider can be analyzed for more accuracy dynamic characteristics.

• Transactions of the Society of Information Storage Systems
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• v.5 no.2
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• pp.58-63
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• 2009

This paper describes the effects of slider behavior over patterned media. The flying characteristics of a slider over patterned media are different from slider flying behavior over conventional plane disk. In order to perform the most realistic simulation of slider flying characteristics over patterned disk surfaces, our simulation approach virtually distributes the grooves on the slider ABS instead of on the disk surface. Also, we define SSFA which is steady-state slider flying attitude. The results show that the more patterned size is small and height is large, the more increased SSFA is. Also if patterned distance is small, then SSFA is increased. In addition, we analyzed the effects of patterned shapes.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.243-244
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• 2002

New type slider with optical components is coming on market for portable and high capacity drive, and it shows great potential in future high performance drive. It is very important that a slider should have a good dynamic behavior. In this paper the dynamic behavior and static characteristics of slider have been investigated numerically by in-house simulation code using FEM.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.1117-1121
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• 2001

The dynamic behavior of slider is investigated using Dynamic Flying Height Tester(DFHT). The dependence of slider's dynamic fluctuation on disk velocity is measured, and a comparison is made with the computational result.

• Tribology and Lubricants
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• v.17 no.1
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• pp.64-71
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• 2001

This paper presents dynamic responses of disk flutter and bump in HDD slider. The slider is modeled for three degree-of-freedom systems, which are capable of lifting, pitching, and rolling motions. In numerical analysis, loads from air pressure, preload and static moments from the slider, and stiffness and damping coefficients of the suspension are considered for investigating the dynamic characteristics analysis. The numerical results are presented as functions of typical parameters such as a disk velocity, stiffness and damping coefficients of the suspension, and skew angle.