Influence of the tool surface micro topography on the tribological characteristics in metal cutting—Part II Theoretical calculations of contact conditions

The tribological conditions at the contact between the cutting tool and the chip are of great importance when analyzing the machining process. By knowing the contact conditions on the rake face of the cutting tool the wear on the clearance and rake face may be predicted in terms of size and type of wear. A certain value of the surface stresses is often thought of as leading to a higher wear rate of the cutting tool and thus a shorter tool life. In this article two different methods for experimentally measuring the contact condition on the clearance and rake face of the cutting tool are presented and illustrated with results obtained while turning AISI 4140. Results are also obtained in terms of how the surface roughness value of the cutting tool influences the contact condition. It was found that the tool surface topography may have a significant impact on the tribological performance during machining.

► Smooth coating reduces the interaction between coating and workpiece material.
► Contact conditions at flank face increases with decreasing coating topography.
► The choice of calculating method strongly influences the contact conditions.
► There exists an optimal value of the coating topography at the rake face.