Experimental study of microtextured surfaces operating under thin-film EHD lubrication conditions

The effect of microdents within thin elastohydrodynamics (EHD) contacts has been studied by two measurement techniques. Phase-shifting interferometry was used to obtain topography of microtextured surface and thin-film colorimetric interferometry provided detailed information about film thickness changes within a lubricated contact. The behavior of microdents has been observed for positive slide-to-roll ratios when the disk is moving faster than the microtextured ball. The depth of microdents has been found to play significant role as to the lubrication films efficiency. The presence of deep microdents within lubricated contact results in film thickness reduction downstream that can even cause lubrication film breakdown. As the depth of microdents is reduced, this effect diminishes and beneficial effect of microdents on film thickness formation has been observed. 'No such an effect of microdent depth on lubricantfilm shape has been observed in case of negative slide-to-roll conditions when microdents do not cause film thickness reduction regardless of their depths. Obtained results suggest that surface texturing using microdents of an appropriate depth could help to increase lubrication films capabilities.