Air Bearing Force Measurement of Pico Negative Pressure Sliders During Dynamic Unload

Chapin, M. C.; Bogy, David B.

doi:10.1115/1.1286151

Cited by 11 publications

(8 citation statements)

References 7 publications

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“…Inaccurate PSA/RSA occurs from manufacturing tolerances, however, and help is required with a leading edge suspension limiter. These issues have been experimentally and theoretically explored in varying detail by Chapin and Bogy (2000), Zeng et al (1999), Hu et al (1999) andPeng (1999). This paper endeavors to experimentally supplement these works and answer specific questions for three different air bearing designs.…”

Section: Introductionmentioning

confidence: 92%

Ramp unloading "footprints"

Yaeger¹,

Hiller²

2002

Microsystem Technologies

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When ramp unloading, the radial distance a slider moves between first touching the ramp and lifting from the disk is called its ''footprint''. Footprints can detract from available recording area. Footprint values were measured for different sub-ambient style air-bearing designs and unloading parameters on a common suspension. Specifically, data was taken over a wide ranging values of PSA/RSA (slider pitch/roll static attitude respectively). Sliders with nominal PSA/RSA regularly lifted gracefully and unaided by suspension limiters within a few mils of travel. As PSA approach zero, however, sub-ambient lifting forces persist, leading-edge limiters engage and footprints extend to 12 mil. Increasing unload velocity increases footprints and slider dynamic vertical motion for nominal PSA/RSA. Surprisingly, for low PSA, slider motion decreases for increasing unload velocity when the leading edge limiter engages.

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Section: Introductionmentioning

confidence: 92%

Ramp unloading "footprints"

Yaeger¹,

Hiller²

2002

Microsystem Technologies

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“…No obvious changes in the number of interference fringes are visible, which can be explained by that at the beginning of an unloading process, a negative pressure slider is usually held to disk surface by its negative air-bearing force. Once the suspension lift force on the slider overcomes the negative air-bearing force, the slider jumps away from the disk surface very fast [16][17][18][19]. Therefore, a photodetector of higher responding frequency is required to record an undistorted unloading calibration than it is required to record an undistorted loading calibration, although the vertical loading and unloading velocities controlled by the moving ramp are identical.…”

Section: Effect Of the Responding Frequency Of The Photodetector On Cmentioning

confidence: 99%

Consideration and compensation for precision optical flying height measurement

Liu

2006

Tribol Lett

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It is a big challenge to determine ultra-low slider flying height accurately. The intensity interferometry flying height testing method is widely used to determine slider flying height. However, the intrinsic measurement errors of the method are becoming non-negligible with the decrease in slider flying height. Strategies have to be developed to minimize the errors. To measure flying height with a normal incidence optical flying height tester, a calibration process is required to determine several constants used in flying height calculation. In practice, the calibration is usually done simply by retracting the slider from the disk and measuring the intensity minima and maxima of the interferogram during the retracting process. It has been demonstrated that the single most important source of error in the flying height measurement is associated with errors in the determination of the intensity maxima and minima. In this work, the effects of optical filter, the responding frequency of photodetector, and the lack of the first order intensity minimum on the determination of the intensity maxima and minima are studied. Methodologies to minimize the errors in flying height measurement caused by the above factors are developed.

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“…For the second run, the equation can be rearranged in the form as eq. (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) to obtain the pressure along y direction:…”

Section: A (5-19)mentioning

confidence: 99%

“…6.12. , (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19) Since the moments show the same trend as the forces do, method can be used to fit the moments. Thus, ,…”

Section: Analysis Of the Positive Moments In Pitch Directionmentioning

confidence: 99%

“…Since a textured landing zone is difficult to be implemented for low flying heights, the load/unload mechanism has widely replaced the conventional zone technology in a hard disk drive. Compared with the contact start-stop (CSS) technology, load/unload mechanism can decrease the possibility of stiction and wear failure, increase the areal density, reduce the power consumption, and improve the shock robustness [14,15].…”

Section: Introduction ______________________________________ 11 Histmentioning

confidence: 99%

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Efficient methodology for analyzing head disk interface with application to unloading process

Liu¹

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Head disk interfaces (HDI) and Load/Unload (L/UL) processes have been studied numerically for over a decade. Several simplified and comprehensive models have been developed to study the HDI in L/UL processes. All existing methods simulated the L/UL behaviors of a slider by iteratively obtaining the instantaneous attitude of a slider through repeatedly solving a modified Reynolds equation which is coupled with the dynamics of the suspension. Despite its relative accuracy, this approach requires huge amount of computational time and power. Hence, developing a simple and efficient model, which is capable of modeling the behavior of the head-disk interface during the L/UL processes, is desired and critical to aid the design process of slide/suspension systems. NOMENCLATURE OF VARIABLES AND SYMBOLS XVI F p total air bearing positive force F n total air bearing negative force P p positive air bearing pressure at the grid points P n negative air bearing pressure at the grid points M p total positive moment M n total negative moment M pp positive moment caused right-hand side positive force M pn positive moment caused left-hand side negative force M np negative moment caused left-hand side positive force M nn negative moment caused right-hand side negative force a, b, c, d variable coefficients changing with θ m, n constants for a slider adjusting the curvature of the fitting f, u, w, v moments curve fitting coefficients

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Air Bearing Force Measurement of Pico Negative Pressure Sliders During Dynamic Unload

Cited by 11 publications

References 7 publications

Ramp unloading "footprints"

Ramp unloading "footprints"

Consideration and compensation for precision optical flying height measurement

Efficient methodology for analyzing head disk interface with application to unloading process

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