On the quasi-rigid body motion of the head actuator assembly in hard disk drives

A quasi-rigid (QR) vibration mode between 3 and 5 kHz is common in current hard disk drives (HDDs), which hinders servo bandwidth improvement and thus limits growth in the areal density (numbers of bits that can be stored per unit area) of HDDs. In this paper, a finite element (FE) model of a head actuator assembly (HAA) is developed and an experimental set-up is established to study the quasi-rigid body mode. The FE model result is compared with the experimental data. It is found that the quasi-rigid body mode is in fact a butterfly-like mode, which integrates the flexibility of the pivot assembly as well as the flexibility and the mass of the whole head actuator body.

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Material Development of Perpendicular Recording for High Areal Density Hard Disk Drives

Journal of Magnetics ◽

10.4283/jmag.2019.24.3.437 ◽

2019 ◽

Vol 24 (3) ◽

pp. 437-447

Author(s):

Kunpot Mopoung ◽

Sakuntam Sanorpim

Keyword(s):

Hard Disk Drives ◽

Hard Disk ◽

Areal Density ◽

Disk Drives ◽

Perpendicular Recording ◽

Material Development

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Design and Dynamics of Flying Height Control Slider With Piezoelectric Nanoactuator in Hard Disk Drives

Journal of Tribology ◽

10.1115/1.2401208 ◽

2006 ◽

Vol 129 (1) ◽

pp. 161-170 ◽

Cited By ~ 27

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.

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Effect of Non-Operational Shock on Interaction Between Suspension Lift-Tab and Load/Unload Ramp

World Tribology Congress III, Volume 1 ◽

10.1115/wtc2005-63558 ◽

2005 ◽

Author(s):

Aravind N. Murthy ◽

Eric M. Jayson ◽

Frank E. Talke

Keyword(s):

Hard Disk Drive ◽

Failure Modes ◽

Hard Disk Drives ◽

Hard Disk ◽

Areal Density ◽

Disk Drive ◽

Disk Drives ◽

Head Disk Interface ◽

Disk Interface ◽

Operational Shock

Most hard disk drives manufactured in the last few years have Load/Unload (L/UL) technology. As opposed to the Contact Start/Stop (CSS) technology, L/UL technology has the advantage of improved areal density because of more disk space availability and better shock performance. The latter characteristic has significant benefits during the non-operational state of the hard disk drive since head/disk interactions are eliminated and the head is parked on a ramp adjacent to the disk. However, even if head/disk interactions are absent, other failure modes may occur such as lift-tab damage and dimple separation leading to flexure damage. A number of investigations have been made to study the response of the head disk interface with respect to shock when the head is parked on the disk ([1], [2]). In this paper, we address the effect of non-operational shock for L/UL disk drives.

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Magnetic Tape: The Challenge of Reaching Hard-Disk-Drive Data Densities on Flexible Media

MRS Bulletin ◽

10.1557/mrs2006.102 ◽

2006 ◽

Vol 31 (5) ◽

pp. 404-408 ◽

Cited By ~ 16

Author(s):

Richard H. Dee

Keyword(s):

Data Storage ◽

Magnetic Tape ◽

Hard Disk Drives ◽

Hard Disk ◽

Areal Density ◽

Operating Conditions ◽

Magnetic Data ◽

Disk Drives ◽

Placement Problem ◽

The Future

AbstractBy the end of 2006, the areal density of magnetic recording on tape will approach that seen in hard disk drives of the early to mid-1990s.These operating conditions are reviewed in relation to the operating conditions deemed necessary for the future of magnetic data storage on tape.What results is a clear set of tasks, encompassing both materials and systems architecture issues, to achieve very high-density data storage on magnetic tape, leading to 10 Tbyte tape cartridge capacities and higher.The key to achieving on tape the areal densities of tens to hundreds of Gbit in.2, common in hard disk drives (HDDs), lies primarily in the properties of the medium itself.As for volumetric density of the storage entity, HDDs and tape cartridges are roughly equivalent.The mechanical dimensional uncertainties that accompany the use of flexible, as opposed to rigid, media means that both the mechanical and magnetic properties of materials play a key role in the future of tape.The need for new architectures to overcome the track placement problem that results from increasing track density on flexible media are reviewed, as well as the “particles in a binder” concept that has served so well as the physical basis of tape media over the past 50 years.

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Servo pattern enhancements for high areal density hard disk drives

10.32657/10356/72656 ◽

2017 ◽

Author(s):

◽

Kun Ma

Keyword(s):

Hard Disk Drives ◽

Hard Disk ◽

Areal Density ◽

Disk Drives

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Passive Vibration Control of the Head Actuator Assembly in Hard Disk Drive

Volume 6C: 18th Biennial Conference on Mechanical Vibration and Noise ◽

10.1115/detc2001/vib-21572 ◽

2001 ◽

Author(s):

LiMei Xu ◽

Sheng Zeng ◽

NingQun Guo ◽

Rongming Lin

Keyword(s):

Rigid Body ◽

Performance Improvement ◽

Hard Disk Drives ◽

Voice Coil Motor ◽

Hard Disk ◽

Disk Drive ◽

Disk Drives ◽

Head Positioning ◽

Hollow Space ◽

The Voice

Abstract It is known that a quasi-rigid body mode exists in hard disk drives in the frequency range from 3 to 6 kHz and it is caused by the flexibility of the pivot, the mass and structure of the head actuator assembly. The mode hinders performance improvement of servo system in bandwidth. In this paper, a tuned damping device is proposed to suppress this mode. The damping device is to be installed on the arm and hollow space within the voice coil motor on the HDDs. The dynamic characteristics of the head actuator assembly with the tuned damping device are measured in both frequency domain and time domain. It is shown that the tuned damping device can work effectively to suppress the quasi-rigid body vibration of the head actuator assembly and minimize the residual vibration in head positioning.

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Impact of radius and skew angle on areal density in heat assisted magnetic recording hard disk drives

AIP Advances ◽

10.1063/1.5007725 ◽

2018 ◽

Vol 8 (5) ◽

pp. 056507

Author(s):

Michael Cordle ◽

Chris Rea ◽

Jason Jury ◽

Tim Rausch ◽

Cal Hardie ◽

...

Keyword(s):

Magnetic Recording ◽

Hard Disk Drives ◽

Hard Disk ◽

Areal Density ◽

Disk Drives ◽

Skew Angle ◽

Heat Assisted Magnetic Recording

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Numerical Study on the Effects of Linear Protrusion on Flow-Induced Carriage Excitation Force in Hard Disk Drives

ASME-JSME 2018 Joint International Conference on Information Storage and Processing Systems and Micromechatronics for Information and Precision Equipment ◽

10.1115/isps-mipe2018-8504 ◽

2018 ◽

Author(s):

Shinji Koganezawa ◽

Shotaro Tsuda ◽

Hiroshi Tani ◽

Renguo Lu ◽

Norio Tagawa

Keyword(s):

Numerical Study ◽

Hard Disk Drives ◽

Leading Edge ◽

Hard Disk ◽

Fe Model ◽

Disk Drives ◽

Fe Method ◽

Mean Velocity ◽

Head Positioning ◽

Excitation Force

The positioning accuracy of magnetic heads need to be improved to increase the recording capacity of hard disk drives. In our previous study, the experimental results confirmed that the head positioning error could be decreased by attaching linear protrusions on the leading edge of the carriage arms. However, the mechanism underlying the phenomenon has not been elucidated. In the current research, we evaluated the effect of leading-edge protrusions on the flow-induced carriage excitation force using the finite element (FE) method analysis and the Hilbert-Huang transform (HHT). We prepared two carriage-arm FE models, with and without linear protrusions, on the leading edges of the arm, and performed the FE analyses. Subsequently, we conducted a frequency analysis by applying the HHT to the simulated torque-disturbance time series of each FE model and the results were later compared. Our results show that the leading-edge protrusions were found to decrease the mean velocity between the arm and the disk, thereby decreasing the vorticity fluctuation in the arm hole, and to decrease the fluctuations in pressure on the outer sidewall of the carriage arm around the coil support.

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