Micro-dimple rolling operation of metallic surfaces

The presence of micro-dimples on the surface of workpieces has long been known to have a positive impact on the friction control and wear resistance at the sliding surfaces. Several manufacturing processes have been used to generate micro-dimples on the surfaces of parts subjected to mechanical contact. Among those methods, metal forming-based techniques have received little attention in the literature mainly due to the challenges present in formation of sub-millimetre dimples using these processes. In this study, a micro-dimple rolling apparatus was developed to rapidly generate dimples with square cross-sections and side dimensions of smaller than 200 μm. The dimples were formed on the surface of a low-carbon structural steel and the effect of generated texture on friction and wear was studied through pin-on-disc test. In comparison with untextured surfaces, the results proved that the dimples formed by the proposed system could effectively reduce the friction coefficient by up to 23% and weight loss due to wear by up to 50%.