Air Bearing Surface Design for Improving Efficiency of Thermomechanical Actuation

Thermomechanical actuation (TMA) at the transducer region of the air bearing surface (ABS) protrudes the transducers toward the recording media, yet also results in greater air bearing slider lift. The ratio of these two effects is defined as the TMA efficiency. An expression based on dimensional analysis is introduced to describe the changes of air bearing forces due to TMA protrusion. A framework is proposed that facilitates optimization of ABS design for improved TMA efficiency. On the basis of the theory presented, several ABSs are designed to have different TMA efficiency. Numerical solutions of these air bearings respect to the protrusion shows agreement with the proposed theory.

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An Air Layer Modeling Approach for Air and Air/Vacuum Bearings

Journal of Manufacturing Science and Engineering ◽

10.1115/1.2831118 ◽

1997 ◽

Vol 119 (3) ◽

pp. 388-392

Author(s):

J. M. Pitarresi ◽

K. A. Haller

Keyword(s):

Load Capacity ◽

Load Resistance ◽

High Load ◽

Air Bearing ◽

Air Bearings ◽

Bearing Surface ◽

Know How ◽

Modeling Approach ◽

Vibrational Characteristics ◽

High Load Capacity

Air layer supported bearing pads, or “air bearings” as they are commonly called, are popular because of their high load capacity and low in-plane coefficient of friction, making them well suited for supporting moving, high accuracy manufacturing stages. Air/vacuum bearings enhance these capabilities by giving the bearing pad load resistance capacity in both the upward and downward directions. Consequently, it is desirable to know how to model the air layer between the bearing pad and the bearing surface. In this paper, a simple finite element modeling approach is presented for investigating the vibrational characteristics of an air layer supported bearing. It was found that by modeling the air layer as a bed of uniform springs who’s stiffness is determined by load-displacement tests of the bearing, a reasonable representation of the response can be obtained. For a bearing supported by air without vacuum, the dynamic response was very similar to that of a freely supported bearing. The addition of vacuum to an air bearing was found to significantly lower its fundamental frequency which could lead to unwanted resonance problems.

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Parametric Investigations at the Head-Disk Interface of Thermal Fly-Height Control Sliders in Contact

Advances in Tribology ◽

10.1155/2012/303071 ◽

2012 ◽

Vol 2012 ◽

pp. 1-11 ◽

Cited By ~ 7

Author(s):

Sripathi V. Canchi ◽

David B. Bogy ◽

Run-Han Wang ◽

Aravind N. Murthy

Keyword(s):

Hard Disk Drives ◽

Air Bearing ◽

Head Disk Interface ◽

Bearing Surface ◽

Surface Design ◽

Disk Interface ◽

Height Control ◽

Experimental Findings ◽

And Control ◽

Fly Height

Accurate touchdown power detection is a prerequisite for read-write head-to-disk spacing calibration and control in current hard disk drives, which use the thermal fly-height control slider technology. The slider air bearing surface and head gimbal assembly design have a significant influence on the touchdown behavior, and this paper reports experimental findings to help understand the touchdown process. The dominant modes/frequencies of excitation at touchdown can be significantly different leading to very different touchdown signatures. The pressure under the slider at touchdown and hence the thermal fly-height control efficiency as well as the propensity for lubricant pickup show correlation with touchdown behavior which may be used as metrics for designing sliders with good touchdown behavior. Experiments are devised to measure friction at the head-disk interface of a thermal fly-height control slider actuated into contact. Parametric investigations on the effect of disk roughness, disk lubricant parameters, and air bearing surface design on the friction at the head-disk interface and slider burnishing/wear are conducted and reported.

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Air bearings in high precision systems

International Journal Sustainable Construction & Design ◽

10.21825/scad.v4i2.1041 ◽

2014 ◽

Vol 4 (2) ◽

Author(s):

I. Cracaoanu ◽

F. Bremer

Keyword(s):

Surface Topography ◽

High Precision ◽

Air Bearing ◽

Test Results ◽

Air Bearings ◽

Bearing Surface ◽

Operational Parameters ◽

Low Friction ◽

Air Supply ◽

Precision System

In high precision system applications low friction levels between components are desirable. Moving heavy parts at high speeds and accelerations without friction is possible by using air bearings. The main failure ofthe air bearings is the wear phenomenon (modification of surface topography) that occurs due to crash into the counterpart when air supply is interrupted. The aim of this research is to investigate different types of air bearings for a large number of crashes using real operational parameters from the field: speed, acceleration, load and supply air pressure. The real crash phenomenon in a high precision machine hasbeen replicated using a test setup. During testing, evolution of air bearing surface topography and air bearing characteristics (gap and flow) after different number of crashes are investigated. Test results showthat some air bearings are not reaching the specified number of crashes due to large defects that occur on the bearing surface. Some specific relations were found between crash defects and parameters such asthe air gap size and the direct contact between opposing surfaces. The preferred type of air bearings shows good performance even above the maximum specified number of crashes. This behavior can be explainedby low friction level during crash tests between the opposing surfaces. The test results from this investigation produced a reliable candidate for air bearings in the high precision system application.

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Air-bearing surface design of an optical flying head considering dynamic characteristics

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1243/13506501jet402 ◽

2008 ◽

Vol 222 (4) ◽

pp. 581-591 ◽

Cited By ~ 2

Author(s):

J Lee ◽

J Kim ◽

N-C Park

Keyword(s):

Dynamic Characteristics ◽

Air Bearing ◽

Bearing Surface ◽

Surface Design

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Air Bearing Surface Designs in Consideration of Thermomechanical Actuation Efficiency

Journal of Tribology ◽

10.1115/1.2958075 ◽

2008 ◽

Vol 130 (4) ◽

Cited By ~ 6

Author(s):

Shuyu Zhang ◽

Sung-Chang Lee ◽

Dongman Kim ◽

Joerg Ferber ◽

Brian Strom ◽

...

Keyword(s):

Flying Height ◽

Recording Media ◽

Air Bearing ◽

Bearing Surface ◽

Affected Area ◽

Pressure Area

Thermomechanical actuation (TMA) at the transducer region of the air bearing surface (ABS) protrudes from the transducer toward the recording media. This actuation induces a change in the air bearing pressure and a concomitant lift of the slider. The actual actuation in flying height divided by the TMA protrusion, defined as the TMA efficiency, is intimately coupled to the ABS design. After introducing an expression describing the changes in the air bearing forces due to the TMA protrusion, three approaches are proposed that facilitate the optimization of the ABS design for improving the TMA efficiency. These approaches include (a) reducing the air bearing pressure, (b) reducing the size of the TMA affected area, and (c) decoupling the peak air bearing pressure area from the TMA affected area. To illustrate these approaches, several ABS designs are evaluated by comparing their TMA efficiencies.

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Design of Low-Speed Spindle Running on Air Bearings Used on Rotary Viscometer

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.531-532.751 ◽

2012 ◽

Vol 531-532 ◽

pp. 751-754

Author(s):

Ying Xue Yao ◽

Hong Bo Wang ◽

Liang Zhou

Keyword(s):

Rotating Cylinder ◽

Air Bearing ◽

Air Bearings ◽

Low Speed ◽

Operation Process ◽

Velocity Attenuation ◽

Rotary Viscometer

A low-speed spindle running on air bearings is presented, it is used on rotary viscometer based on velocity attenuation of rotating cylinder. Principle of spindle is introduced, it is composed of a low speed motor and an air bearing. The low speed motor is a coupling of two motors. Design of the spindle shows the structure of it. Materials of the spindle are selected. The spindle is machined and operation process of it shows it is suitable for driving part of rotary viscometer based on velocity attenuation of rotating cylinder.

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Experience and results obtained at the ESRF with high-precision air bearing motion systems

Diamond Light Source Proceedings ◽

10.1017/s204482011000064x ◽

2011 ◽

Vol 1 (MEDSI-6) ◽

Author(s):

P. Marion ◽

L. Ducotte ◽

M. Nicola ◽

H. P. van der Kleij ◽

L. Eybert ◽

...

Keyword(s):

High Precision ◽

High Accuracy ◽

Air Bearing ◽

Air Bearings ◽

Positioning Accuracy ◽

Point Of Interest ◽

Air Film

In high-accuracy motion stages, the positioning accuracy at the point of interest is strongly influenced by guiding errors: for translation motions, straightness errors and angular errors (pitch, yaw and roll); for rotation motions, axial, radial and tilt errors. When air bearings are used for guiding, the air film averages out local irregularities of bearings surfaces, which helps reduce guiding errors considerably. Some results obtained with air bearing precision systems designed and manufactured by specialized companies and tested at ESRF are described below.

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