Experimental characterization of friction coefficient at the tool–chip–workpiece interface during dry cutting of AISI 1045

Abstract

This paper presents the application of an experimental set-up able to simulate similar tribological phenomena as the ones occurring at the tool–chip–workpiece interface in metal cutting. Especially, this system enables to reach contact pressures up to 3GPa and sliding velocities between 0 and 300m/min. In addition to classical measurements of friction coefficients, the system provides information about the heat flux transmitted to pins, which enables to estimate the heat partition coefficient along the interface. This system has been applied to the characterization of the tool–chip–workpiece interface during dry cutting of an AISI 1045 steel with TiN coated carbide tools. It has been shown that the sliding velocity is the most influential parameter whereas contact pressure has only a limited influence. However, three friction regimes can be distinguished. In the first regime (low sliding velocity), friction coefficient is almost constant whereas heat flux transmitted to cutting tools is proportional to sliding velocity. In the second regime (intermediate sliding velocity), friction coefficient decreases very significantly with sliding velocity whereas heat flux remains almost constant. In the third regime (high sliding velocity), friction coefficient is not affected by sliding velocity whereas heat flux transmitted to the cutting tools increases again.