Observation of Slider Landing Process in Hard Disk Drive

2011

Microsyst Technol

Thermal flying height (TFC) controlled slider has been introduced in hard disk drive recently. Flying height at the read/write elements of the slider is controlled by thermal pole tip protrusion. Interactions between the TFC slider and disk can be very gentle because the low flying height thermal protrusion area is usually very small. It is still a big challenge to detect very gentle interactions. In this work, a very sensitive method to study very gentle slider-disk interaction in frequency domain has been developed and details of the TFC slider-disk interactions from gentle to strong have been revealed. It is proved that higher heating power is required to initiate the vibration in which higher stiffness part of the slider air-bearing is involved.

Section: Introductionmentioning

confidence: 99%

Experimental study of slider–disk interaction process with thermal-flying-height controlled slider

2011

Microsyst Technol

“…Slider flying speed can reach 50 m/s and the pressure in slider-disk interface can be higher than 100 atmospheres. Deep understandings about slider-lubricant-disk interaction are required to build a stable slider-disk interface [2]. Issues ignored before have to be considered very carefully now in designing sliders [3].…”

Section: Introductionmentioning

confidence: 99%

Dominant Factors in Lubricant Transfer and Accumulation in Slider-Disk Interface

2007

Tribol Lett

Lubricant transfer from disk to slider and lubricant accumulation on slider are very important in designing a stable slider-disk interface of ultra-low spacing. In this article, the effects of different parameters on the lubricant transfer and accumulation are studied and the reasons behind the effects are explained. Furthermore, the time for the lubricant transfer to reach steady state is estimated. It is found that lubricant molecular weight plays a dominant role in the lubricant transfer and accumulation. Lubricant transfer and accumulation decrease dramatically with the increase in lubricant molecular weight. Lubricant transfer also strongly depends on lubricant thickness and bonding ratio on disk surface. A thinner lubricant and higher lubricant bonding ratio on disk surface reduce lubricant transfer obviously, which results in less lubricant accumulation. A diamond-like-carbon (DLC) overcoat of low adsorption area density on slider surface can reduce lubricant transfer and accumulation, especially for lubricant of low molecular weight. Lubricant accumulation increases with disk velocity and increases slightly with the decrease in slider flying height. Lubricant accumulation can be reduced by minimizing the area of slider pad. Lubricant transfer and accumulation become worse at higher ambient temperature. It takes seconds for lubricant of low molecular weight to reach steady transferred thickness and hours for lubricant of high molecular weight to reach the steady state.

“…Therefore, apart from the FHs, dynamic flying attitude (pitch and roll angles) of the slider can also be determined. It has been used to study dynamic load/unload [20] and slider landing processes [21]. The system is used to study the slider-bump interaction process in this work.…”

Section: Introductionmentioning

confidence: 99%

Slider–bump contact and flying height calibration

Wang

et al. 2006

Tribol Lett

Self Cite

It is a big challenge to determine ultra-low slider flying height accurately. The standard bump disk method is probably the most reliable and acceptable method so far. One of the key issues to determine slider-flying height with the bump disk method is the complicated slider-bump interaction process and the possible disturbance of the bumps on the slider flying performance. Our knowledge about the slider-bump interaction process is still very limited due to the lack of an effective and powerful experimental technique to study it. In this work, the slider-bump interaction process was studied with a dynamic flying height-attitude (3D) system. The interaction process was also simulated to compare with the experimental observations and to help determine the sliderbump contact points in the experimental observations. The accuracy of flying height (FH) calibration with the bump disk method and the minimum slider-bump interference height required for the testing system used in this study to detect the onset of sliderbump contact were analyzed and discussed. It is proved that the 3D system is a very useful and powerful tool for the application. Many details of the slider-bump interaction process can be revealed with the 3D system. It is found that the calibrated FH is much more accurate than that predicated by the simulations.