PERFORMANCE PREDICTION MODELS FOR TURNING WITH ROUNDED CORNER PLANE FACED LATHE TOOLS. II. VERIFICATION OF MODELS

Abstract

ABSTRACT Extensive numerical simulation and experimental verification of the predictive force and surface roughness models for turning operations have been carried out encompassing the domain of cutting conditions recommended in practice. It has been shown that the three force models predicted very similar qualitative and plausible trends in the tangential, feed and radial force components as well as chip flow angle with changes in the many operation variables. The experimental testing involved about 500 turning cuts over a wide range of inclination angles, normal rake angles, major cutting edge angles, corner radius, feed and depth of cut. All the qualitative trends in the forces and chip flow angle noted in the simulation studies have been experimentally confirmed for all the three force models for both TiN coated and uncoated tools. The first two force models predictions correlated very well with the experimental results while only reasonable correlation was found with the third (approximate) model. The surface roughness predictive models were found to be adequate for turning with TiN coated HSS tools only while empirical equations were still necessary for reliable estimates of surface roughness for turning with the uncoated HSS tools. This investigation has shown that comprehensive and quantitatively reliable predictive models for the forces, power, chip flow angle and surface roughness can be established from fundamental cutting the- ory and analysis. In particular, the findings of this investigation provide further evidence in support of the generic nature of the ‘unified mechanics of cutting approach’ to technological performance prediction and the potential of the predictive surface roughness models for machining with coated tools.