SURFACE TOPOGRAPHY OF OPERATED SLIDE JOURNAL MICRO-BEARINGS USED IN HDD

Abstract

In this paper author present results of measurements of slide journal micro-bearings surface topography measured with an atomic force microscope (AFM). The results of measurements of surface topography were presented in the form of surface topography maps, three-dimensional graphs and some examples of selected cross-sections of investigated surface in the form of profile graphs. Measurements of surface topography were made for journals and sleeves of slide journal micro-bearings from personal computers' hard disc drives, with the Atomic Force Microscope NT-206 produced in MTM in Minsk, Republic of Belarus. In this research author used two identical sets of micro-bearings from 2.5” HDD Samsung HM160HI 5400rpm and 3.5” HDD Seagate Barracuda 7200.10 ST380815AS 7200 rpm hard disc drives. First set of those four microbearings worked for a year at rated RPM continuously (i.e. 24 hours a day). Second set of the same micro-bearings also worked for a year at rated RPM, but in intermittent mode (i.e. 15 minutes on, 15 minutes off). The values of profile roughness parameters R a and R q and the distance between maximum peak height and maximum valley depth are presented as well. The application SurfaceXplorer® was used for processing and visualization of the data obtained from AFM NT-206, which besides from generating 2D, 3D and profile diagrams, was used to calculate and draw graph of height distribution. Surface topography of investigated bearings sleeves was also measured using Hommeltester T8000-R60 profilometer. Those measurements give information about micro-grooves dimensions and location. On the surfaces of studied micro-bearings, some micro-grooves can be found in form of herringbone, with depth about 1.5 Pm and width 150 Pm. Received information about micro-grooves geometry will allow developing proper theory of hydrodynamic lubrication for micro-bearings with micro-grooves.