Thermal flying-height control sliders are currently used in most hard disk drives as an approach to increase the capacity and reliability. This paper discusses our recent numerical studies of the sliders’ flying performances, namely, the heat transfer between the slider and the disk, the flyability of the sliders at different altitudes, and the effect of the disk’s lubricant and roughness on the slider’s flying stability. We validate previous investigations based on a heat transfer model derived from the first-order slip theory and identify the instability regimes for a slider flying over a lubricated rough disk.
Meyer, DW, Kupinski, PE, and Liu, JCSlider with temperature responsive transducer positioning. U. S. Patent5991113, 23 November 1999.
2.
Kurita, M. , and Suzuki, K.Flying-height adjustment technologies of magnetic head sliders. IEEE Trans Magn2004; 40: 332-336.
3.
Shiramatsu, T., Atsumi, T., Kurita , M., Shimizu, Y., and Tanaka, H.Dynamically controlled thermal flying-height control slider. IEEE Trans Magn2008; 44: 3695-3697.
4.
Juang, JY, Chen, D., and Bogy, DBAlternate air bearing slider designs for areal density of 1Tb/in2 . IEEE Trans Magn2006; 42: 241-246.
5.
Juang, JY, and Bogy, DBAir-bearing effects on actuated thermal pole-tip protrusion for hard disk drives. ASME J Tribol2007; 129: 570-578.
6.
Juang, JY, Nakamura, T., Knigge, B., Luo, YS, Hsiao, W-C., Kuroki, K., et al. Numerical and experimental analyses of nanometer-scale flying height control of magnetic head with heating element. IEEE Trans Magn2008; 44: 3679-3682.
7.
Zhang, S., Lee, S-C., Kim, D., Ferber, J., Strom, B., and Tyndall, G.Air bearing surface designs in consideration of thermo-mechanical actuation efficiency. ASME J Tribol2008; 130: 041901.
8.
Li, H. , Yin, C-T., and Talke, FEThermal insulator design for optimizing the efficiency of thermal flying height control sliders . J Appl Phys2009; 105: 07C122.
9.
Aoki, K., and Watanabe, T.Nonlinearity of thermal spacing control in hard disk drives. IEEE Trans Magn2009; 45: 816-821.
10.
Zhou, WD, Liu, B., Yu, SK, Hua, W., and Wong, CHA generalized heat transfer model for thin film bearings at head-disk interface . Appl Phys Lett2008; 92: 043109.
11.
Zhou, WD, Wong, CH, Liu, B., Yu, SK, and Hua, W.Effects of temperature dependent air properties on the performances of a thermal actuated slider. Tribol Int2009 ; 42: 902-910.
12.
Reynolds, O.On the theory of lubrication and its application to Mr. Beauchamp Tower’s experiments, including an experimental determination of the viscosity of olive oil. Philos Trans R Soc London1886; 177: 157-234.
13.
Batchelor, GKAn Introduction to fluid dynamics. Cambridge: Cambridge University Press , 1967.
14.
Schaaf, SA, and Chambré, PLFlow of rarefied gases. Princeton, NJ: Princeton University Press, 1961.
15.
Bird, GAMolecular gas dynamics and the direction simulation of gas flows. New York: Oxford University Press, 1994.
16.
Burgdorfer, A.The influence of the molecular mean free path on the performance of hydrodynamic gas lubricated bearing. ASME J Basic Eng1959; 81: 94-100.
17.
Hsia, YT, and Domoto, GAAn experimental investigation of molecular rarefaction effects in gas lubricated bearings at ultra-low clearances. ASME J Lubr Technol1983; 105: 120-130.
18.
Mitsuya, Y.Modified Reynolds equation for ultra-thin film gas lubrication using 1.5-order slip-flow model and considering surface accommodation coefficient. ASME J Tribol1993 ; 115: 289-294.
19.
Wu, L. , and Bogy, DBNew first and second order slip models for the compressible Reynolds equation. ASME J Tribol2003; 125: 558-561.
20.
Shen, S., and Chen, G.A kinetic-theory based first order slip boundary condition for gas flow. Phys Fluids2007; 19: 085101.
21.
Bahukudumbi, P., and Beskok, A.A phenomenological lubrication model for the entire Knudsen number. J Micromech Microeng2003; 12: 873-884.
22.
Cercignani, C.Rarefied gas dynamics: from basic concepts to actual calculations. New York: Cambridge University Press, 2000.
23.
Sone Y.Molecular gas dynamics: theory, techniques, and applications. Boston, MA: Birkhäuser, 2006 .
24.
Bhatnagar, PL, Gross, EP, and Krook, M.A model for collision processes in gases I: small amplitude processes in charged and in neutral one-component systems . Phys Rev1954; 94: 511-525.
25.
Fukui, S., and Kaneko, R.Analysis of ultra-thin gas film lubrication based on linearized Boltzmann equation: first report- derivation of a generalized lubrication equation including thermal creep flow. ASME J Tribol1988; 110: 253-262.
26.
Fukui, S., and Kaneko, R.Analysis of ultra-thin gas film lubrication based on linearized Boltzmann equation (influence of accommodation coefficient). JSME Int J1987; 30: 1660-1666.
27.
Fukui, S., and Kaneko, R.A database for interpolation of Poiseuille flow-rates for high Knudsen number lubrication problems. ASME J Tribol1990; 112: 78-83.
28.
Kang, SC, Crone, RM, and Jhon, MSA new molecular gas lubrication theory suitable for head-disk interface modeling . J Appl Phys1999; 85: 5594-5596.
29.
Chen, D., and Bogy, DBA comparison of two rarefaction models in the compressible Reynolds equation used in air bearing design for hard disk drives. CML Technical Report 2005-10 . Berkeley, CA: Computer Mechanics Laboratory, Department of Mechanical Engineering, University of California , 2005.
30.
Shen, C.Use of degenerated Reynolds equation in solving the microchannel flow problem . Phys Fluids2005; 17: 046101.
31.
Wu, L.A slip model for rarefied gas flows at arbitrary Knudsen number. Appl Phys Lett2008; 93: 253103.
32.
Zhang, S., and Bogy, DBA heat transfer model for thermal fluctuation in a thin slider/disk air bearing . Int J Heat Mass Transfer1999 ; 42: 1791-1800.
33.
Chen, L., Bogy, DB, and Strom, B.Thermal dependence of MR signal on slider flying state. IEEE Trans Magn2000; 36: 2486-2489.
34.
Lees, L.Kinetic theory description of rarefied gas flow. J Society Ind Appl Math1965; 12: 278-311.
35.
Vincenti, WG , and Kruger, CHIntroduction to physical gas dynamics. New York: Wiley, 1965.
36.
Ju, YSThermal conduction and viscous heating in microscale coquette flow. ASME J Heat Transfer2000; 122: 817-818.
37.
Chen, D., Liu, N., and Bogy, DBA phenomenological heat transfer model for the molecular gas lubrication system in hard disk drives. J Appl Phys2009 ; 105: 084303.
38.
Liu, N., Zheng, J., and Bogy, DBPredicting the flying performance of thermal flying-height control sliders in hard disk drives . J Appl Phys2010; 108:016102.
39.
Lu, S.Numerical simulation of slider air bearing. PhD Thesis. Berkeley, CA: Department of Mechanical Engineering,University of California, 1997.
40.
Zheng, J., and Bogy, DBThermal fly-height control (TFC) code user’s manual. CML Technical Report 2009-06. Berkeley, CA: Computer Mechanics Laboratory, Department of Mechanical Engineering, University of California, 2009.
41.
ANSYS Inc.ANSYS 11.0 user’s manual. 2007.
42.
Liu, B., Zhang, MS, Yu SK, Hua , W., Ma , YS, Zhou, WD, et al. Lubricant-surfing recording and its feasibility exploration. IEEE Trans Magn2009 ; 45: 899-904.
43.
Gupta, V. , and Bogy, DBDynamics of sub-5nm air bearing sliders in the presence of electrostatic and intermolecular forces at the head disk interface . IEEE Trans Magn2005 ; 41: 610-615.
44.
Greenwood, JA , and Williamson , JBP.Contact of nominally flat surfaces. In: Proceedings of the Royal Society of London, A112, 1966, pp.300-319.
45.
Stanley, HM, Etsion, I., and Bogy, DBAdhesion of contacting rough surfaces in the presence of sub-boundary lubrication. ASME J Tribol1990; 112: 98-104.
46.
Muller, VM , Derjaguin, BV, and Toporov, YPOn two methods of calculation of the force of sticking of an elastic sphere to a rigid plane . Colloids Surf1983; 7: 251-259.
47.
Cox, BJ , and Bogy, DBThe CML air bearing design program (CMLAir) version 7 user manual. CML Technical Report 2007-13. Berkeley, CA: Computer Mechanics Laboratory, Department of Mechanical Engineering, University of California, 2007.
