Dynamic Analysis of Sliding Contacts at Head-Disk Interface

2002 ◽  
Author(s):  
T.-J. Chuang ◽  
S. M. Hsu
Keyword(s):  
Data Storage ◽  
High Speed ◽  
Time History ◽  
Disk Drive ◽  
Element Model ◽  
Disk Surface ◽  
Magnetic Data ◽  
Head Disk Interface ◽  
Sliding Contacts ◽  
Disk Interface

As magnetic data storage technology moves towards higher areal data density with higher rotational speeds and lower flying heights, the propensity of severe sliding contacts at the head-disk interface is bound to increase. The tribological performance of the head-disk interface will have significant impact on the durability and service life of the hard disk drive (HDD). A 3D finite element model is constructed to simulate the high speed impact event of a slider on the disk surface. For a given design of the disk with known layer thicknesses and properties, as well as that of the slider with its surface texture, the model predicts contact zone, depth force and duration as well as time-history of energy transfer and its partition, substrate stress and plastic zone for a given impact velocity. The effects of the material properties and layer thicknesses on the performance of the HDD are investigated.

Atomistic simulation method in head-disk interface of magnetic data storage systems

2012 ◽  
Vol 111 (7) ◽  
pp. 07B717 ◽  
Author(s):  
Robert L. Smith ◽  
Pil Seung Chung ◽  
Sesha Hari Vemuri ◽  
Geun-Young Yeom ◽  
Lorenz T. Biegler ◽  
...  
Keyword(s):  
Data Storage ◽  
Atomistic Simulation ◽  
Storage Systems ◽  
Simulation Method ◽  
Magnetic Data Storage ◽  
Magnetic Data ◽  
Head Disk Interface ◽  
Disk Interface

Multi-scale/multi-physical modeling in head/disk interface of magnetic data storage

2012 ◽  
Vol 111 (7) ◽  
pp. 07B712 ◽  
Author(s):  
Pil Seung Chung ◽  
Robert Smith ◽  
Sesha Hari Vemuri ◽  
Young In Jhon ◽  
Kyungjae Tak ◽  
...  
Keyword(s):  
Data Storage ◽  
Physical Modeling ◽  
Magnetic Data Storage ◽  
Magnetic Data ◽  
Head Disk Interface ◽  
Disk Interface ◽  
Multi Scale

Experimental Study of High-Speed Contact at Head-Disk Interface in a Magnetic Hard Disk

2005 ◽  
Author(s):  
Mingwu Bai ◽  
Stephen M. Hsu
Keyword(s):  
Acoustic Emission ◽  
High Speed ◽  
Hard Disk ◽  
Disk Drive ◽  
Test Method ◽  
Head Disk Interface ◽  
Emission Analysis ◽  
Disk Interface ◽  
Emission Signal ◽  
Carbon Overcoats

Tribological performance of the head-disk interface will have significant impact on the performance and durability of the hard disk drive. A high-speed contact test method has been developed for the purpose of evaluating nanometer-thick lubricant film/carbon overcoats materials on hard-disk surfaces. Four different thickness overcoats were used in high speed contact experiments. High speed contact force was calculated based on the calibration of acoustic emission signal by proposed ball dropping tests. Acoustic emission analysis, frequency spectrum analysis, and surface morphology imaging were used to analyze the deformation and fracture at high speed contacted area. The availability of an experimental technique enables effective screening of different material chemistries and lubricant combinations to improve the level of protection for hard disk technology.

Head-disk interface design in magnetic data storage

2012 ◽  
Vol 111 (7) ◽  
pp. 07B721 ◽  
Author(s):  
Sesha Hari Vemuri ◽  
Pil Seung Chung ◽  
Robert L. Smith ◽  
Nae-Eung Lee ◽  
Lorenz T. Biegler ◽  
...  
Keyword(s):  
Data Storage ◽  
Interface Design ◽  
Magnetic Data Storage ◽  
Magnetic Data ◽  
Head Disk Interface ◽  
Disk Interface

Effects of Air Bearing Stiffness on a Hard Disk Drive Subject to Shock and Vibration

2003 ◽  
Vol 125 (2) ◽  
pp. 343-349 ◽  
Author(s):  
Eric M. Jayson ◽  
J. Murphy ◽  
P. W. Smith ◽  
Frank E. Talke
Keyword(s):  
Finite Element ◽  
Hard Disk Drive ◽  
Hard Disk ◽  
Disk Drive ◽  
Element Model ◽  
Air Bearing ◽  
Head Disk Interface ◽  
Disk Interface ◽  
Wide Range ◽  
Bearing Stiffness

A finite element model of a hard disk drive (HDD) is developed to investigate the transient response of an operational HDD subject to shock and vibration. The air bearing stiffness of the head disk interface is determined from a finite element solution of the Reynolds equation and approximated with linear springs. The structural response is analyzed for several types of sliders with a wide range of air bearing stiffness. Results show the response of the head-disk interface subject to shock and the modes excited by vertical and lateral vibrations of the HDD.

A Method to Detect Head Media Spacing Change in a Hard Disk Drive Using an Embedded Contact Sensor

2019 ◽  
Author(s):  
Rahul Rai ◽  
Puneet Bhargava ◽  
Bernhard Knigge ◽  
Aravind N. Murthy
Keyword(s):  
Hard Disk Drives ◽  
Hard Disk ◽  
Disk Drive ◽  
Disk Surface ◽  
Physical Change ◽  
Disk Drives ◽  
Head Disk Interface ◽  
Disk Interface ◽  
Frequency Components ◽  
Contact Sensor

Abstract Growth in the demand for higher capacity hard disk drives (HDD) has pushed the requirement for head-media spacing (HMS) to sub-nanometer levels. The drop in operational clearance makes a head-disk interface (HDI) more susceptible to potential head-wear and contamination related issues. Such degradation processes are often accompanied by a noticeable shift in the head-disk clearance. Hence monitoring an interface for a spacing change can be helpful in early detection of its imminent failure. In this paper, we present a method to detect the change in head-disk spacing using an embedded contact sensor (ECS). This technique involves the analysis of ECS dynamic response for an interface that is subjected to heater induced spacing modulations. As the head moves closer to the disk surface, the magnitude of the ECS frequency components can be used to determine the ‘characteristic spacing’ which can be used as a metric to detect any physical change for a given interface.

Numerical Simulation on Lubricant Recovery After Depletion

2013 ◽  
Author(s):  
Peng Yu ◽  
Weidong Zhou ◽  
Shengkai Yu
Keyword(s):  
High Speed ◽  
Short Range ◽  
Hard Disk ◽  
Corrosion Damage ◽  
Areal Density ◽  
Disk Drive ◽  
Disk Surface ◽  
Lubricant Layer ◽  
Continuous Increase ◽  
Disk Interface

In magnetic recording, the hard disk rotates at a high speed, with the slider flying above it. To protect the disk and slider from corrosion damage, contact scratching, high friction and wear, a thin lubricant layer is coated on the disk surface. With the continuous increase in the hard disk drive (HDD) areal density, the spacing between the head and the media is rapidly approaching the sub-nanometer regime, which demands the thickness of lubricant to be molecularly-thin. At such a nanoscale head-disk interface, the short-range forces and the air shear force may cause significant lubricant migration [1, 2]. The lubricant may pile up, and/or be picked up by the slider [3], which in turn affects the flyability of the slider. Meanwhile, the short-range forces such as Van de Waals forces may cause lubricant instability issues [1].

Air Bearing Slider-Disk Interface for Single-Sided High Speed Recording on a Metal Foil Disk

2007 ◽  
Vol 129 (3) ◽  
pp. 562-569 ◽  
Author(s):  
James White
Keyword(s):  
Data Storage ◽  
High Speed ◽  
Hard Disk ◽  
Disk Drive ◽  
Flying Height ◽  
Metal Foil ◽  
Air Bearing ◽  
Recording Head ◽  
Disk Interface ◽  
Air Bearing Slider

There are disk-drive data storage applications best served by single-sided recording configurations. These include situations where (i) storage requirements can be achieved on a single side of a disk and (ii) dimensional constraints on the disk drive prohibit the presence of a recording head and its associated mounting device on each side of the disk. Even if dimensional requirements are not a concern, the most cost-effective and operationally efficient slider-disk air-bearing interface for single-sided recording is one that does not include an air-bearing slider, pressure pad, or other air-bearing structure on the nondata side of the disk. A metal foil disk offers some of the best characteristics of both the hard disk and floppy disk for digital data storage. It offers hard disk recording densities, increased shock resistance, reduced manufacturing cost, and requires less operational energy than a hard disk. However, use of a conventional recording head slider assembly without opposing air-bearing support for single-sided recording on a high-speed metal foil disk presents a fundamental problem because the air-bearing surface of the slider produces a net transverse force to the disk. This force causes the disk to deflect and can result in flying height and stability problems at the slider-disk interface. The current work describes an air-bearing interface for low flying height single-sided recording on a high-speed metal foil disk that minimizes disk deflection and instability without the presence of air-bearing components on opposing sides of the disk. The new interface utilizes a vacuum cavity-type air-bearing with little or no preload. Examples will be presented and discussed for the new interface that illustrate the flying characteristics of a picosized slider on a 1.8in. stainless steel disk with thickness of 25.4μm.

Slider Overcoats for Enhanced Interface Durability in Magnetic Recording Applications

1995 ◽  
Vol 117 (1) ◽  
pp. 86-93 ◽  
Author(s):  
S. K. Ganapathi ◽  
Timothy A. Riener
Keyword(s):  
Magnetic Recording ◽  
Friction And Wear ◽  
Disk Drive ◽  
Disk Surface ◽  
Electrical Performance ◽  
Head Disk Interface ◽  
Bearing Surface ◽  
Component Level ◽  
Disk Interface ◽  
Significant Performance

The effects on tribological performance of air bearing surface overcoats on magnetic recording sliders are presented. Both component level and disk drive level testing indicate that significant performance enhancements are afforded by the overcoat, and that both stiction/friction and wear of the head/disk interface are reduced, thus increasing interface durability. The degradation in electrical performance of the heads due to the presence of the overcoat is shown to be consistent with that predicted by the Wallace equation. In addition, it is shown that the performance enhancements of the overcoat are achieved only in the presence of lubricant on the disk surface, suggesting that the overcoat lubricant interaction may be more benign than the interaction of the lubricant with the slider material.

SYSTEM RELIABILITY WITH COMPETING COMPONENTS AND LOAD SHARING — A HDD HEAD-DISK INTERFACE PERSPECTIVE

2011 ◽  
Vol 18 (04) ◽  
pp. 377-390 ◽  
Author(s):  
FENG-BIN SUN ◽  
DONALD GILLIS
Keyword(s):  
Data Storage ◽  
System Reliability ◽  
Data Transfer ◽  
Disk Drive ◽  
Load Sharing ◽  
Head Disk Interface ◽  
Life Distribution ◽  
Disk Interface ◽  
Inverse Power Law ◽  
Two Factors

The authors of this paper present a quantitative insight of a long argued question in hard disk drive (HDD) industry about the reliability effects of the number of head-disk interfaces (HDI). The competition between complexity and data transfer load is modeled from system reliability perspective: competing components with load sharing. Product failure probability ratio and steady-state MTTF ratio between different data storage capacities are derived in terms of their head-disk interface number ratio and data transfer ratio. It is found that the reliability dominance of these two factors is conditional to the mathematical characteristics of their governing failure physics. The detailed discussion is conducted on the system reliability with head-disk interface failures governed by Weibull life distribution and Inverse Power Law stress-life relationship.

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