• Proceedings of the KSME Conference
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• 2001.06d
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• pp.585-588
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• 2001

Particle contamination on the data storage disks has been a serious problem for magnetic hard disk drive manufacturers. For high storage optical disks, such as DVD-ROM/RAM or NFR (near field recording) system, particle-induced damages can be also detected because only a few micrometer particles can prevent read/write signal from optical lens. The increasing areal density and smaller bit size accelerates particle induced damages on the optical disk. One of the methods to prevent particle contamination on the optical disk surface is to handle the disk enclosed in a cartridge like a modern DVD-RAM disk. However, even for a perfectly sealed disk drive, particles are found inside the drive. The other method is to improve disk surface characteristics. Particle contamination on the surface can be reduced by proper selection of disk coating materials. [n this paper, particle detachment ratios for CD (compact disk), DVD (digital versatile disk), HD (magnetic hard disk), HD with Jut lubricant, and aluminosilicate substrate HD were investigated. Surface roughness and surface energy of the test disks were compared with the particle detachment ratios. Proper substrate and lubricant characteristics to reduce particle contamination on the disk surface were found.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.8 s.227
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• pp.976-983
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• 2004

In high-density hard disk drives, the slider should be made to fly close to the magnetic recording disk to generate better signal resolution and at an increasingly high velocity to achieve better data rate. The slider disk interaction in CSS (contact-start-stop) mode is an important source of particle generation. Contamination particles in the hard disk drive can cause serious problems including slider crash and thermal asperities. We investigated the number and the sizes of particles generated in the hard disk drive, operating at increasing disk rotational speeds, in the CSS mode. CNC (condensation nucleus counter) and PSS (particle size selector) were used for this investigation. In addition, we examined the particle components by using SEM (scanning electron microscopes), AES (auger electron spectroscopy), and TOF-SIMS (time of flight-secondary ions mass spectrometry). The increasing disk rotational speed directly affected the particle generation by slider disk interaction. The number of particles that were generated increased with the disk rotational speed. The particle generation rate increased rapidly at motor speeds above 8000 rpm. This increase may be due to the increased slider disk interaction. Particle sizes ranged from 14 to 200 nm. The particles generated by slider disk interaction came from the lubricant on the disk, coating layer of the disk, and also slider surface.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.88-95
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• 2005

The head to disk spacing must be decreased to increase recording densities in hard disk drives. Recently, to decrease the head to disk spacing, smooth disk having no bumps onto the lading zone has used. In this research, we compared the number of particles generated in HDD with smooth and textured disks. We used a sampling method using a particle sampler and a CPC (condensation particle counter) to detect particles in HDD. First, we sampled and counted panicles generated with disk rotational speed and various rest times when the smooth disk and textured disks were used, then analyzed the sampled particles by SEM (scanning electron microscopy) and AES (auger electron spectroscopy). In results of measuring particles, more particles in case of LZT disk drive generated than that of the smooth disk drive in all test modes. The number of particles generated in the smooth disk was very low. The particle generation increased as the rest time increased (smooth/LZT disks) and more particles in case of LZT disk drive generated than that of the smooth disk drive. In results of analyzing particle components, Al, Ti, Si components were detected and we could not found differences between components in case of smooth/LZT disk drive.

• Transactions of the Society of Information Storage Systems
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• v.2 no.2
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• pp.123-129
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• 2006

The head to disk spacing must be decreased to increase recording densities in hard disk drives. Recently, to decrease the head to disk spacing, smooth disk having no bumps onto the lading zone has used. In this research, we compared the number of particles generated ill HDD with smooth and textured disks. We used a sampling method using a particle sampler and a CPC (condensation particle counter) to detect particles in HDD. First, we sampled and counted particles generated with disk rotational speed and various rest times when the smooth disk and textured disks were used, then analyzed the sampled particles by SEM (scanning electron microscopy) and AES (auger electron spectroscopy). In results of measuring particles, more particles in case of LZT disk drive generated than that of the smooth disk drive in all test modes. The number of particles generated in the smooth disk was very low. The particle generation increased as the rest time increased (smooth/LZT disks) and more particles in case of LZT disk drive generated than that of the smooth disk drive. In results of analyzing particle components, Al, Ti, Si components were detected and we could not found differences between components in case of smooth/LZT disk drive.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.6
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• pp.744-752
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• 1999

Particle contamination in a hard disk drive has been recognized as an important issue because particles can significantly affect the reliability of the drive. In this study, characteristics of the particle generation in a hard disk drive during the start/stop period were investigated. The number of particles generated in the drive was measured at 5 locations by using condensation nucleus counters(CNC) with sampling probes. It was found that most of particles were generated whenever the drive started or stopped. The number of particles detected by the condensation nucleus counter depended on sampling parameters including sampling location, shape of sampling probe, and sampling velocity.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.4
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• pp.183-188
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• 2003

Particulate contamination is known to be a significant cause of failures of removable storage media. In this work, the effect of particles on the surface damage of removable hard disk media was investigated. The particles of different materials and size were introduced to the Head Disk Interface (HDI) using a particle injection system. It was round that the particles of particulate size and property serious damaged the media. This study showed that cleaning pad is effective for reducing particle contamination, except fer the particles of specific size and property. As a means to remove the particles of specific sire. the concept of using a stepped taper at the leading edge of the slider is proposed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.946-949
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• 2002

Particulate contamination is known to be a significant cause of failures of removable storage media. In this work, The effect of particles on the surface damage of removable hard disk media was investigated. The particles of different materials and size were introduced to the head-disk interface using a particle injection system. It was found that the particles of particulate size and property serious damaged the media. This study showed that cleaning pad is effective for reducing particle contamination, except for the particles of specific size and property. As a means to removed the particles of specific size, the concept of using a stepped taper at the leading edge of the slider is proposed.

• Tribology and Lubricants
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• v.16 no.6
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• pp.415-424
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• 2000

The use of magnetoresistive (MR) head requires much tighter control of particle contamination in a drive since loose particles on the disk surface will generate thermal asperities (TA). In this study, a spinoff test was performed to investigate the adhesion and removal capability of a particle to disk surface. Numerical simulation was also performed to investigate dominant factor of particle detachment and to support experimental results. It was shown that particles are detached from the disk surface by the moment derived from the centrifugal force and the drag force and that the centrifugal force and capillary force are the dominant force, which determines spin-off of a particle on the disk surface. Removal of particles smaller than several micrometers, which are the main source of TA generation, is extremely difficult since the adhesion forces exceed the centrifugal force. Lubricant types and manufacturing process also influence the particle removal. Lower bonding ratio and lower viscosity of the lubricant will help to increase the removal rate of the particles from the disk surface.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.5 s.236
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• pp.599-608
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• 2005

Controlling particle contamination is important to increase storage capacity as the flying height of a slider in a hard disk drive decreases. Since precise detection and analysis of particles are primary steps of particle control in a HDD, many researchers have used sampling methods. In this paper, we newly designed a particle sampler and conducted performance evaluation of the sampler. Also, we conducted particle sampling from the HDD using the particle sampler and analysis of sampled particles by SEM and AES. Experimental results show that the particles generated by the slide-disk interaction mainly came from the disk surface.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.7 s.238
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• pp.795-804
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• 2005

As the flying height of a slider in a hard disk drive decreases, the slider and disk are more likely to come in contact and generate contamination particles. Since particle contamination can cause serious problems including thermal asperity, it must be prevented to increase storage capacity. When particles are generated in a HDD, particles can be charged and have a few number of elementary charges. In this paper, the size distribution of particles and electrical current due to particle according to the disk rotational speed were measured. Also, the average number of elementary charges was calculated from experimental data. SEM images of particles were obtained by using a particle sampler designed in our laboratory.