Dynamics of head-disk interface in hard disk drives during operational shock

2016 ◽  
Vol 22 (6) ◽  
pp. 1389-1395 ◽  
Author(s):  
Shengkai Yu ◽  
Jianqiang Mou ◽  
Wei Hua ◽  
Weidong Zhou ◽  
Chye Chin Tan
Keyword(s):  
Hard Disk Drives ◽  
Hard Disk ◽  
Disk Drives ◽  
Head Disk Interface ◽  
Disk Interface ◽  
Operational Shock

Effect of Non-Operational Shock on Interaction Between Suspension Lift-Tab and Load/Unload Ramp

2005 ◽  
Author(s):  
Aravind N. Murthy ◽  
Eric M. Jayson ◽  
Frank E. Talke
Keyword(s):  
Hard Disk Drive ◽  
Failure Modes ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Areal Density ◽  
Disk Drive ◽  
Disk Drives ◽  
Head Disk Interface ◽  
Disk Interface ◽  
Operational Shock

Most hard disk drives manufactured in the last few years have Load/Unload (L/UL) technology. As opposed to the Contact Start/Stop (CSS) technology, L/UL technology has the advantage of improved areal density because of more disk space availability and better shock performance. The latter characteristic has significant benefits during the non-operational state of the hard disk drive since head/disk interactions are eliminated and the head is parked on a ramp adjacent to the disk. However, even if head/disk interactions are absent, other failure modes may occur such as lift-tab damage and dimple separation leading to flexure damage. A number of investigations have been made to study the response of the head disk interface with respect to shock when the head is parked on the disk ([1], [2]). In this paper, we address the effect of non-operational shock for L/UL disk drives.

On the Touchdown-Takeoff Hysteresis Observed at the Head-Disk Interface in Hard Disk Drives

2005 ◽  
Author(s):  
Rohit P. Ambekar ◽  
David B. Bogy
Keyword(s):  
Experimental Approach ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Intermolecular Forces ◽  
Disk Drives ◽  
Head Disk Interface ◽  
Contributing Factors ◽  
Factors Affecting ◽  
Disk Interface

The touchdown-takeoff velocity hysteresis observed in hard disk drives during CSS or L/UL tests is analyzed using an experimental approach. Tests similar to L/UL were conducted for different slider-disk combinations at different humidities. Factors affecting the touchdown and takeoff velocity were identified on the basis of their domain of operation. It is concluded that the intermolecular forces and meniscus forces are contributing factors to hysteresis, which is also influenced by disk topography and slider dynamics.

Experimental Investigation of Heat Flux at the Head-Disk Interface in Hard Disk Drives

2016 ◽  
Author(s):  
Yuan Ma ◽  
David B. Bogy
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Strong Increase ◽  
Disk Drives ◽  
Head Disk Interface ◽  
Disk Interface ◽  
Contact Points ◽  
Phonon Conduction

In hard disk drives (HDDs), Thermal Fly-Height Control (TFC) is used to control the head disk spacing for reading or writing data. In order to monitor the spacing and detect possible contacts between the head and disk, a resistive temperature sensor, called Touch-Down Sensor (TDS), is embedded in the slider near potential contact points of the slider against the disk. Understanding the mechanisms of heat transfer across the head-disk interface (HDI) is of major importance, because it is closely related to the design of HDDs, including lubricant flow and contact issues, especially for Heat Assisted Magnetic Recording (HAMR) drives. In this paper, we conducted a series of experiments both on rotating and on non-rotating disks with TDS to find the cause of head temperature change and to validate the heat transfer theory based on phonon conduction. From the experiment, it is shown that air bearing cooling is not responsible for the cooling that occurs in the last nanometer before contact. Based on phonon conduction predictions, we should expect a decrease in slope of the non-contact curve as the spacing becomes less than 1 or 2 nm because of the strong increase in the heat flux due to phono conduction in this range.

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