• Transactions of the Society of Information Storage Systems
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• v.3 no.2
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• pp.81-85
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• 2007

Reliability of a hard disk drive depends on the head disk interface (HDI) characteristics. Particularly, the disk media and the head can be damaged due to contact between the two components during operation. The contact may occur due to particles being introduced into the disk/slider interface or due to direct contact between the slider and the disk. Such contacts may be induced by external vibration or abnormal operation of the HDI. In this work the characteristics of scratches generated on the disk surface were investigated. The scratches were generated by impacting the hard disk. The type of scratches was analyzed with respect to their shape and dimensions.

• Tribology and Lubricants
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• v.20 no.6
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• pp.322-329
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• 2004

Recently, a load/unload(L/UL) system is adopted to the hard disk drive(HDD) due to its advantages such as lower power consumption, larger data zone, simpler fabrication of disk due to no bumped parking zone, and rarer contact between slider and media. An analysis of the transient motion for the slider is very important to design an air bearing surface(ABS) of the slider to secure the stable performance of the system. During the L/UL process, however, there are several issues occurred such as contact or collision between slider and media. Sometimes this will cause the system failure. In this study, the dynamics of a pico slider during the loading process are investigated through numerical simulation using FEM analysis and experiment. Ramp profile and angular velocity of the swing arm actuator are very important parameters for the design of L/UL system to avoid collision between slider and disk.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.277-278
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• 2002

Magnetron and Ion beam sputtering were used to texture the air-bearing surface of magnetic recording sliders. Flying height measurements and Laser-Doppler interferometry were used to compare the 'flyability' of textured and untextured sliders. Lubricant redistribution on the disk surface caused by slider/disk interactions was investigated using scanning ellipsometry (Surface Reflectance Analyzer (SRA)). The results show that slider surface texture causes only small changes in the flying height of sliders but reduces slider in-plane and out-of-plane vibrations. Textured sliders were found to cause less lubricant depletion on the disk surface than untextured sliders.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.140-143
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• 2006

Load/Unload(L/UL) technology includes the benefits, that is, increased areal density, reduced power consumption and improved shock resistance. The main issues of L/UL are no slider-disk contact and no media damage. To make sure L/UL stability, we consider many design parameters in L/UL systems. This paper is focused on disk design parameters through designing a disk bump in outer guard band(OGB). In the case of bump design on the disk, we create a bump by changing bump design parameters as like size and amplitude. From dynamic analysis, we choose optimal bump model with the highest flying height and the longest rising time. When a slider passes over a bump in dynamic system, the slider rise above bump according to bump shape. On the basis of this rising effect on the bump, we apply bump design to classical L/UL system having slider-disk contact possibility. This study is based on the simulation, we finally realize improved slider unloading performance by applying slider dynamic result on unload simulation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.6
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• pp.871-883
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• 1997

Kinetodynamics of a cam driving slider mechanism consists of kinematic analysis and force analysis. The kinematic analysis is to determine the kinematic characteristics of a cam driving mechanism and a slider mechanism. The force analysis is to determine the joint forces of links, the contact forces of the cam and follower, and the driving torque of a main shaft. This paper proposes a close loop method and a tangent substitution method to formulate the relationships of kinematic chains and to calculate the displacement, velocity and acceleration of the cam driving slider mechanism. Also, and instant velocity center method is proposed to determine the cam shape from the geometric relationships of the cam and the roller follower. For dynamic analysis, the contact force and the driving torque of the cam driving slider mechanism are calculated from the required sliding forces, sliding motion and weight of the slider.

• Journal of the Korean Society for Railway
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• v.15 no.3
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• pp.224-230
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• 2012

The wearing slider of the rail motor car's pantograph is considerable changed by the type and the material properties. Especially, precipitation and arc influences are main factors decided to life time of wearing slider and contact wire. This study is wearing phenomenon analysis of Cu-type wearing slider with high electric conductivity and resistance arc through experiment by running train. Author observed that wearing phenomenon of Cu-type wearing slider with normal and abnormal wearing characteristics and comparatively analysis precipitation, mileage and weight influences of exchanged Cutype and Fe-type wearing sliders. In this paper result showed that necessity for the application which is the Fe-type of wearing slider had superior wear resisting capacity etc., through tribology approach.

• Tribology and Lubricants
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• v.17 no.4
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• pp.312-320
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• 2001

In magnetic hard disk drives, higher areal recording density requires reduction of head-disk spacing. To overcome the increase of stiction associated with reduction of head-disk spacing, a padder slider, which adds pads to slider's air bearing surface, can be one of the practical solution for sub 20 nm flying height, and even for near contact recording. This study investigated the tribological characteristics of a padder slider. A padder slider took off slowly but showed less friction force than a normal slider. The hot/dry CSS test and drag test indicated that pad wear of a padder slider was negligible. The tribological performance of disk is an important factor to be considered. In particular, less carbon overcoat layer of the disk will result in higher stiction and wear in slider/disk interface. In conclusion, a padder slider shows encouraging tribological performances for practical use in HDD.

• KSTLE International Journal
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• v.1 no.1
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• pp.29-33
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• 2000

In this study, a methodology is developed and confirmed to find the physical contact between the slider and disc due to the defects of disk during head seeking operation using acoustic emission (AE) signal. The head/disk contact was detected during random and standard seeks, whereas no contact was detected during track fellowing. During standard and random seeks, the torsion mode of slider excitation was observed at 680KHz. Therefore, it is thought that AE technique can be used as an alternative method of the glide test by monitoring existence of the torsional mode of the slider during seek operation or can be used to detect the spacing loss during seeking operation. By appropriately choosing the location of the sensor an order of magnitude increase in the sensitivity for RMS AE signal is observed. Therefore we can find take-off velocity clearly with high signal to noise ratio of AE signal.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.887-887
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• 2004

The areal density of the hard disk drive(HDD) has been increased due to technological advances recently. To achieve the high areal density magnetic recording requires an extremely small gap between the air-bearing surface (ABS) and disk. At the same time, the slider mass and size should be reduced to minimize the physical contact under the operational and environmental conditions. Almost all of 2.5＂HDD companies will get ready for adoption of FEMTO slider and already utilized the small slider. FEMTO and small size slider will be mainstream in the 2.5" and other small form factor HDD in the near future. In this study, the flying characteristic of FEMTO slider was examined. Based on the simulation, FEMTO slider is very stable in flying dynamic under the disk modulation, however the flying height sensitivity of the manufacturing tolerances is much bigger than PICO slider. And the other characteristics like impulse response and load/unload dynamic were also examined in this study.tudy.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.243-247
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• 2001

As a means to reduce stiction in the landing zone padded sliders can be used. In this work the performance of padded slider was investigated using a commercial spin stand. The friction and acoustic emission signals were measured during the experiment. It is shown that padded slider show superior friction and AE characteristics. However, the wear properties of the pads should be further Improved.