Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/27916
Title: METHODS TO CHARACTERISE THE PERFORMANCE OF HEAD DISK INTERFACE USING A MULTIFUNCTIONAL SPINSTAND
Authors: BUDI SANTOSO
Keywords: In-situ Fly Height, Thermal Fly Height Control, Slider dynamics, Media Defect, Laser Doppler Vibrometer, Tribocharging
Issue Date: 12-Jan-2011
Source: BUDI SANTOSO (2011-01-12). METHODS TO CHARACTERISE THE PERFORMANCE OF HEAD DISK INTERFACE USING A MULTIFUNCTIONAL SPINSTAND. ScholarBank@NUS Repository.
Abstract: A multifunctional spinstand has been developed to integrate Head Disk Interface (HDI) measurement tools such as Acoustic Emission (AE), Laser Doppler Vibrometer (LDV) and missing pulse electronics to provide concurrent measurement capability to characterize slider dynamics and media defects. In this case, multifold information can be obtained that will help to remove spurious information present in any single scan. It has been shown that the LDV¿s capability to detect media defects is comparable to the Optical Surface Analyzer (OSA) and through a special enhancement method, the LDV can also be used concurrently with missing pulse to perform media defect certification that is fast and more efficient. Measurement of slider dynamics are carried out in two different test conditions. In the first test condition, mapping of slider-defect interaction provides two-dimensional information on the size of the interaction regime and nature of interactions. Such a mapping approach is suggested for useful characterization of sliders, in particular, thermal activated protrusions from Thermal Fly Height Control (TFC) technology. Secondly, slider dynamics of ultra-low flying heights are studied using thermal protrusion. Here, contact induced vibration is analyzed in both frequency and time domain to better understand the touch down process. It is pointed out that slider dynamics is a slider design specific characteristics and frequency domain analysis is shown to be useful to characterize the slider¿s mechanical response. Time domain information helps to reveal slider¿s interaction with media surface. Concurrent methods can help to provide better understanding of slider-lube interactions using sensitivity of different measurement methods. Tribocharging is a critical HDI phenomenon at ultra-low flying heights. Tribocharge buildup at the slider-disk interface was investigated by measuring tribocurrent at the head disk interface in three regimes: slider flying and disk deceleration, slider dragging at constant speed, and disk acceleration to slider flying. In general, the tribocharging is different for deceleration and acceleration regimes and is shown to be related to velocity and acceleration. The onset appearance and changes to the tribocurrent occur at different disk velocity (and have different peak values) for different initial velocities used. Additional tribovoltage and AE measurements are performed to correlate and help explain the tribocharging occurrence at the interface.
URI: http://scholarbank.nus.edu.sg/handle/10635/27916
Appears in Collections:Master's Theses (Open)

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