Efficient Machining of Micro-dimples for Friction Reduction

This paper presents new process strategies to machine micro-dimples for friction reduction. By these strategies the inner and outer diameter surfaces as well as the face surfaces of cylindrical components are machinable in an efficient way. Furthermore, the investigations indicate that the density, the arrangement and the geometry of the micro-dimples can be directly set by the process strategy and the process input parameters. In ring-on-disc tribometer experiments the potential of the machined micro-dimples was particularly emerged for low sliding speeds in the mixed friction area. Here high dimple densities, small dimple depths and small dimple flank angles have proven to be favourable for friction reduction. Current work is focused on the machining of already honed cylinder liners. For this, an innovative tool concept compensating form deviations of the clamped cylinder liner is under development.