A Model of Slider/Disk Interface Wear for Proximity Recording

1996 ◽  
Vol 118 (4) ◽  
pp. 813-818 ◽  
Author(s):  
Yufeng Li ◽  
Aric Menon
Keyword(s):  
Material Properties ◽  
Hard Disk Drives ◽  
Air Bearing ◽  
Disk Drives ◽  
Carbon Overcoat ◽  
Interface Evolution ◽  
Disk Interface ◽  
Recording Process ◽  
Surface Topographies ◽  
Slider Air Bearing

Slider/disk interface wear is inevitable for ultra-low flying hard disk drives and is the central issue for proximity recording. While disk wear has been addressed in the literature, slider wear has been largely considered to be trivial and is ignored. However, with the improvement of disk overcoat and introduction of diamond-like-carbon overcoat on slider air bearing surface, the surface hardnesses of the slider and disk are approaching each other and, therefore, the slider surface wear becomes significant or, in some conditions, even dominant. In this study, a theoretical model is developed for semi-steady-state slider/disk interface evolution of proximity recording which takes account of both the disk and slider wear. It includes the effects of the air bearing characteristics, pitch stiffness, material properties, and surface topography of both the slider and disk. Numerical results are illustrated for typical proximity recording interface, where the evolutions of the slider, disk, contact force, and pitch angle are evaluated for various air bearing stiffnesses, material properties, and surface topographies. This model is intended to provide some fundamental understanding of the slider/disk interface evolution during proximity recording process.

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.

Lubricant Depletion and Disk-to-Head Lubricant Transfer at the Head-Disk Interface in Hard Disk Drives

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Rohit P. Ambekar ◽  
David B. Bogy ◽  
C. S. Bhatia
Keyword(s):  
Hard Disk Drives ◽  
Areal Density ◽  
Disk Drives ◽  
Lubricant Thickness ◽  
Lubricant Transfer ◽  
Disk Interface ◽  
Slider Air Bearing ◽  
Disk Lubricant ◽  
The Stability ◽  
Lubricant Performance

As the head-disk spacing reduces in order to achieve the areal density goal of 1 Tb/in.2, the dynamic stability of the slider is compromised due to a variety of proximity interactions. Lubricant pickup by the slider from the disk is one of the major reasons for the decrease in the stability as it contributes to meniscus forces and contamination. Disk-to-head lubricant transfer leads to lubricant pickup on the slider and also causes depletion of lubricant on the disk. In this paper, we experimentally and numerically investigate the process of disk-to-head lubricant transfer using a half-delubed disk, and we propose a parametric model based on the experimental results. We also investigate the dependence of disk-to-head lubricant transfer on the disk lubricant thickness, lubricant type, and the slider air bearing surface (ABS) design. It is concluded that disk-to-head lubricant transfer occurs without slider-disk contact and there can be more than one timescale associated with the transfer. Furthermore, the transfer increases nonlinearly with increasing disk lubricant thickness. Also, it is seen that the transfer depends on the type of lubricant used and is less for Ztetraol than for Zdol. The slider ABS design also plays an important role, and a few suggestions are made to improve the ABS design for better lubricant performance.

Multi-Body Modeling Effects on the Head-Disk Interface During Operational Shocks in Hard Disk Drives

2013 ◽  
Author(s):  
Liping Li ◽  
David B. Bogy
Keyword(s):  
Hard Disk Drives ◽  
Base Plate ◽  
Hard Disk ◽  
Portable Devices ◽  
Air Bearing ◽  
Disk Drives ◽  
Disk Interface ◽  
Mechanical Shocks ◽  
The Stability ◽  
Multi Body

Over the past decade, there has been an increase in the demand of hard disk drives (HDD) used in portable devices. In such applications HDDs are often subjected to mechanical shocks. Hence it is important to study the stability of mobile drives during operational shocks (op-shock) in order to improve their shock performance. Former numerical investigations [1–3] used either detailed structure models and simplified air bearing models or vice versa to understand the HDI response during an opshock event. In 2012, Rai and Bogy [4] proposed a method in which both the HDD components and the air bearing were modeled in detail and were coupled with each other. However, in this model the head actuator assembly (HAA) was assumed to be amounted on a fixed support and hence the flexibility of the base plate and those effects on the HAA were neglected. In this study, we model the HAA as mounted on the base plate to investigate the effects of HDD components on the shock performance of mobile drives.

Optimization of Air Bearing Slider Design

2005 ◽  
Author(s):  
Wending Fang ◽  
Yujuan Wang ◽  
Yunfei Chen
Keyword(s):  
Simulated Annealing ◽  
Simulated Annealing Algorithm ◽  
Optimal Algorithm ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Flying Height ◽  
Air Bearing ◽  
Disk Drives ◽  
Slider Air Bearing ◽  
Bearing Design

Hard disk drives continue to increase the data storage density. The parameters of the head slider flying attitude must satisfy very strict performance goals. This paper focuses on the topic of the simulated annealing algorithm when it is applied to the problem of slider air bearing design in hard disk drives. The objective is to minimize the static flying height, to keep the pitch angle within a reasonable range, and to minimize the roll angle. The design variables include recess depth and geometry configuration of the slider air bearing surface. A typical tri-pad slider was taken as the physical model to demonstrate the validity of the optimal algorithm. Results show that simulated annealing is efficient for the optimization of the slider air bearing design. The static air bearing characteristics were enhanced significantly.

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