Modeling and Simulation for Head/Disk Electromechanical Systems Interface During Load/Unload Process of a Hard Disk Drive

2016 ◽  
Author(s):  
Nasim Mirnateghi ◽  
Sandip D. Kulkarni ◽  
JiangHong Ding ◽  
Ashok Desai
Keyword(s):  
Hard Disk Drive ◽  
Large Scale ◽  
Voice Coil Motor ◽  
Hard Disk ◽  
Operating Mode ◽  
Disk Drive ◽  
Spindle Motor ◽  
Detailed Model ◽  
Feasibility Assessment ◽  
And Performance

This paper presents a novel design and reliability assessment simulator focusing on HDD (Hard Disk Drive)’s L/UL (Load and Unload) operations. The model is structured to incorporate theoretical effects of environmental factors, component variations, and temperature effects in addition to empirical dependencies on product operating mode. The simulator includes detailed model of VCM (Voice Coil Motor), spindle motor, PLSI (Power Large Scale Integration), and all other related components and their effects on the load and unload operations. The tool can be used for feasibility assessment of new electromechanical designs and available design margins, and it is also a reliable tool to provide accurate tunings for FW (firmware) Load, Unload, Emergency Unload and EPOR (Emergency Power Off Retract). The simulator is also capable of accurately estimating the potential DPPM (Defective Part Per Million) related to the various potential failures using latest statistical analysis. The predictions and performance reliability of the model have been verified experimentally through comparison with HDD product reliability test data.

Deformation of Hard Disk Drive Media Caused by Thermal Stress and Induced Air Flow

2014 ◽  
Vol 1061-1062 ◽  
pp. 866-873
Author(s):  
Pakornwit Padtha ◽  
Kiatfa Tangchaichit
Keyword(s):  
Thermal Stress ◽  
Hard Disk Drive ◽  
High Speed ◽  
Air Flow ◽  
Voice Coil Motor ◽  
Hard Disk ◽  
Disk Drive ◽  
Spindle Motor ◽  
High Rotational Speed ◽  
The Media

The spindle motor in a hard disk drive spins at a high rotational speed. These rotations generate air flow and thermal stress. Air flow is induced by the surface roughness of the media that is moving at a high speed through air. This air passes over the surface of many parts in the drive, including the media. Thermal stress is generated by heat in the parts, e.g. voice coil motor, pre-amplifier, slider pole tips, which are heated by electric power and by the spinning of the spindle motor. The air flow and thermal stress cause a change in the media shape called deformation.Simulation results show the trend of deformation has more bending when the slider moves outward from the media axis. The pressure acted more on the underside than on the upper side which caused the media to bend up to the top cover side of hard disk drive. The maximum deformation, 15 μm, occurred at the rim of media while the distance between the media and the slider is 30 μm; thus they did not contact each other.

Spindle Motor Simulator for Hard Disk Drive: A Design Tool for Predicting Spinup Time and Headroom Safety for High Volume Manufacturing

2016 ◽  
Author(s):  
Sandip D. Kulkarni ◽  
Nasim Mirnateghi ◽  
JiangHong Ding ◽  
Ashok Desai
Keyword(s):  
Hard Disk Drive ◽  
Large Scale ◽  
Failure Modes ◽  
Hard Disk ◽  
High Volume ◽  
Disk Drive ◽  
Spindle Motor ◽  
Design Tool ◽  
Model Parameters ◽  
Large Sample Size

This paper presents a novel simulator for hard disk drive (HDD) spindle motor, developed to accelerate motor design verification for large volume product by predicting spin-up time (a performance metric) and voltage headroom (an important reliability metric). The simulator comprises of a BLDC (brushless DC) spindle motor model, firmware block, and power device block. The simulator integrates physics-based model structures with more complex measurement-based behavioral aspects at various temperatures and speeds. All model parameters incorporate realistic environmental factors and part variations; simulation of large sample size of in silico drive design based on Monte Carlo (MC) selection of parameters yields theoretical results capable of predicting defective parts per million in field. The simulator uses a modular approach allowing changing of firmware settings, details of Power Large Scale Integration (PLSI), and motor mechanics, which are product specific. This simulator model can be used for feasibility assessment of new electromechanical designs, available design margins for motor selection and it is also a reliable tool to provide boundaries for firmware (FW) settings to avoid reaching failure modes.

Superlubricity Relevant in Hard Disk Drive Applications

2016 ◽  
Author(s):  
Shou-Mo Zhang ◽  
Cuong-C. Vu ◽  
Qun-Yang Li ◽  
Norio Tagawa ◽  
Quan-Shui Zheng
Keyword(s):  
Temperature Dependence ◽  
Hard Disk Drive ◽  
Large Scale ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Disk Drive ◽  
Force Sensor ◽  
Lubricant Layer ◽  
Single Crystalline ◽  
Crystalline Graphite

Reduction of head-media spacing (HMS) keeps crucial during the increase of areal density of hard disk drives (HDD). The design of hard disk drive with a superlubric interface is reported with two schemes for HDI design to realize superlubricity. For the first scheme, the DLC layer is kept on the disk while removing the lubricant layer. The DLC layer on the transducer is replaced by graphene-like layer. The direct contact between head and disk could reduce the HMS to about 2.3 nm. For the second scheme, the DLC layer on disk is further replaced by graphene and the HMS could be reduced to below 1 nm. For the first scheme, the basic proof of concept experiments are conducted using micro-scale graphite island samples. Ultralow COF, with the average of 0.0344 on the interface of single crystalline graphite surface and DLC substrate is demonstrated by AFM. What’s more, the temperature dependence of friction between single crystalline graphite and DLC is measured by micro-force sensor mounted on micro-manipulator. The results show that heating helps to significantly decrease the friction. Desorption of contaminants along the interface is speculated to be the key mechanism for temperature dependence of friction. This work provides the concept of large-scale superlubricity relevant in HDD applications, which could be a promising technology to ultimately reduce HMS for future HDI development.

Design and Performance Test of Comb-Shaped Clamp/Spacer for Improvement of Recirculation Filter Efficacy in a Hard Disk Drive

2009 ◽  
Vol 45 (1) ◽  
pp. 201-205 ◽  
Author(s):  
Sung-Eun Park ◽  
Dae-Young Lee ◽  
Jae-Hong Park ◽  
Tae-Sik Kang ◽  
Jin-Gyoo Yoo ◽  
...  
Keyword(s):  
Hard Disk Drive ◽  
Performance Test ◽  
Hard Disk ◽  
Disk Drive ◽  
And Performance

Realization of a hard disk drive head servo-positioning system with a voltage-driven voice-coil motor

2003 ◽  
Vol 9 (4) ◽  
pp. 271-281 ◽  
Author(s):  
R. Oboe ◽  
F. Marcassa ◽  
P. Capretta ◽  
F. Chrappan Soldavini
Keyword(s):  
Hard Disk Drive ◽  
Voice Coil Motor ◽  
Hard Disk ◽  
Disk Drive ◽  
Positioning System

Vibration Characteristics of a Rotor-Flexible Disk System: In Case of HDD Spindle-Motor System

1999 ◽  
Author(s):  
D. C. Han ◽  
S. H. Choi ◽  
K. B. Park ◽  
S. C. Jung
Keyword(s):  
Hard Disk Drive ◽  
Hard Disk ◽  
Disk Drive ◽  
Spindle Motor ◽  
Vibration Characteristics ◽  
Rotating Shaft ◽  
Disk System ◽  
Assumed Mode Method ◽  
Mode Method ◽  
Flexible Disk

Abstract In this paper we investigate the vibration characteristics of a rotor system with flexible disks. The coupled vibration mode between rotating shaft and the flexible disk are analyzed for lateral and axial vibrations respectively. Gyro and sheer effects are considered for the modeling of lateral vibrations. An assumed mode method was used for the disk modeling considering gyro effects. For a numerical example hard disk drive is considered. The natural frequencies of the motor-spindle system with flexible disk of hard disk drive was calculated and compared to the experimental data.

Experimental Characterization Techniques for High Performance Hard Disk Drive Ball Bearing Spindle Motors

1999 ◽  
Author(s):  
Andrew Chong ◽  
Lu Yi ◽  
S. X. Chen ◽  
Q. D. Zhang
Keyword(s):  
Hard Disk Drive ◽  
High Speed ◽  
High Performance ◽  
Ball Bearing ◽  
Hard Disk ◽  
Disk Drive ◽  
Spindle Motor ◽  
Hard Disks ◽  
Steel Balls ◽  
Test Requirements

Abstract The key task for the spindle motor in a hard disk drive is to provide stable, reliable and consistent turning power for many years to allow the hard drive to function properly. As hard disks become more advanced, virtually every component in them is required to do more & perform better, and the spindle motor is no exception. Increasing the rotational speed at which the platters spin means that the data can be read off the disk faster, and also reduces rotational latency, the time that the heads must wait for the correct sector number to come under the head. For this reason, there has been a push to increase the speed of the spindle motor. Since the launching of hydro-dynamic bearing spindle technology for high speed application will not be in due course, current ball bearing technology will still be around for a couple of years provided the spindle speed does not exceed around 15 Krpm. Therefore optimizing the steel balls in the spindle system is an alternative to deal with the ever-increasing performance requirements of the hard disk drive. To accomplish this, we have to understand the failure phenomenon in the spindle, thereby set test requirements to overcome the failure mechanism. These test requirements will help us to understand the performance characteristic and robustness of the spindle motor. In this paper, the test requirements is set according to modal, load and vibration methods to quantify the hard disk drive ball bearing spindle motor.

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