Experimental investigation on friction under metal cutting conditions

This paper presents an experimental test to analyze friction phenomena within the tool-chip interface in metal cutting. Therefore, it is designed to obtain experimental data under conditions that are characterized by high contact temperatures, pressures and sliding velocities. The experimental approach is derived from an orthogonal cutting process, modified to a high speed forming and friction process by using an extremely negative rake angle. Such an angle suppresses the formation of chips and results in a smooth plastic flow of metal over the tool surface which generates very high contact temperatures and therefore approaches the conditions of metal cutting. Investigations were conducted for three workpiece materials AISI 1045, AISI 4140 and Inconel 718 in combination with uncoated WC-6Co cemented carbide tools. For these materials, the experimental analysis shows significant thermal softening within the contact interface caused by frictional heat generation and plastic deformation. To account for the observed phenomena, a temperature dependent friction model is proposed and evaluated by a finite element model. (C) 2013 Elsevier B.V. All rights reserved.