Numerical cutting modeling gives access to thermo-mechanical. variables such as stress, strain and temperature that in some cases are not easily measurable through experimental tests. Thus, it offers an alternative route to improve the knowledge of several fields related to the machining process: cutting tool, parts manufacturing and tool and workpiece materials. However data related to workpiece material and tool-chip contact need to be improved, before it can be offered as a reliable method for industry. This paper presents a sensitivity study of friction coefficient carried out in a 2D model developed with Abaqus/Explicit 6.1, in order to define their influence on numerical results. The presented results, relate to AISI-4140 and cemented carbide grade P10 tool, demonstrate the great influence of the friction parameter over the outcome of numerical results.