Contact and friction analysis at tool-chip interface to high-speed machining

ABSTRACT

Numerical approaches to high-speed machining are necessary to increase productivity and to optimise tool wear and residual stresses. In order to apply such approaches, the rheological behaviour and the friction model have to be correctly determined. The existing numerical approaches that are used with current friction models do not generate good correlations of the process variables, such as the cutting forces or toolchip contact length. This paper proposes a new approach for characterizing the friction behaviour at the toolchip interface in the zone near the cutting edge. An experimental device was designed to simulate the friction behaviour at the tool-chip interface. During the upsetting-sliding test conducted on this devise, the indenter rubs the specimen with a constant velocity, generating a residual friction track. The contact pressure and friction coefficient are determined from the test’s numerical model and are then used to identify the friction data according to the interface temperature and the sliding velocity. These initial findings can be further developed for implementation in FEA machining models in order to increase productivity.