Surface topography of operated slide journal micro - bearings used in computer fans

In this paper authors present results of measurements of slide journal bearings surface topography measured with a profilometer and an atomic force microscope (AFM). Surface topography of investigated bearings (i.e. journals and sleeves) was measured using the Hommeltester T8000- R60 profilometer. The results of these measurements give information about micro-grooves dimensions and location. Measurements of surface topography were made for journals and sleeves of slide journal micro-bearings from personal computers fans, with the Atomic Force Microscope NT-206 produced in MTM in Minsk, Republic of Belarus. The results of measurements of surface topography were presented in the form of surface topography maps, threedimensional graphs and some examples of selected cross-sections of investigated surfaces in the form of profile graphs. The values of profile roughness parameters Ra and Rq and the distance between maximum peak height and maximum valley depth are presented as well. The application SurfaceXplorer registered trademark 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 graphs of height distribution. In this research authors used two identical sets of micro-bearings. The investigated bearings are: a) Kama Flow SP0825FDB12H fan with grooved surface of bearing sleeve, b) Xilence Case fan which sleeve surface was without grooves. First set of that micro-bearings functioned for a year at rated RPM continuously (i.e. 24 hours a day). Second set of the same micro-bearings also functioned for a year at rated RPM, but in intermittent mode (i.e. 15 minutes on, 15 minutes off). On the surfaces of studied micro-bearings some microgrooves can be found in form of herringbone, with depth about 1-2..m and width 100-150..m. Received information about microgrooves geometry will help to develop proper theory of hydrodynamic lubrication for micro-bearings with microgrooves and allows determining how the mode of operating affects on the wear of co-operating surfaces.