New tribometer designed for the characterisation of the friction properties at the tool/chip/workpiece interfaces in machining

This work deals with the development of a new tribometer designed for the characterisation of the frictional properties at the tool/chip/ workpiece interfaces in cutting processes. Based on a plane-sphere contact configuration, the experimental set-up enables a continuous regeneration of the pinworkmaterial contact. The average contact pressure can be selected up to 3 GPa under sliding velocities reaching 16 m/s. Under such severe conditions, which are not reachable with conventional tribometers, the apparent friction coefficient is quantified in parallel to the heat flux transmitted to the pin. This new system has been applied to the characterisation of the frictional properties during the dry machining of a 27MnCr5 annealed steel with a carbide cutting tool. The influence of the sliding velocity and of an additional TiN layer deposited by PVD on the carbide pins has been investigated in dry conditions. It has been shown that the sliding velocity is the more influential parameter, followed by the coating. Copyright © 2007 John Wiley & Sons, Ltd.