Frictional property of a 3D-capillary-structured surface fabricated by selective laser melting

In this study, a self-oil-circulating structure, termed a 3D-capillary structure, has been proposed to improve the frictional properties of sliding elements. The 3D capillary structure can collect excessive lubricant from a sliding surface and resupply to the interface by capillary action. Selective laser melting was utilized to fabricate the 3D capillary structure because of its complex 3D micro-structure. The oil supplying function of the 3D capillary structure was confirmed by performing a reciprocating sliding test with digital camera observation. The frictional property was evaluated using four specimens with different surfaces: (1) non-textured surface, (2) conventional dimpled surface, (3) 3D-capillary-structured surface and (4) surface with 3D capillary structure and conventional dimpled structure. Experiment results showed that the 3D capillary structure exhibited excellent anti-seizure properties. It was also concluded that the specimen with a mixed 3D capillary structure and conventional dimple had the best anti-seizure and low friction properties.