Experimental and analytical balance sheet in turning applications

In orthogonal, oblique, and 3D cutting, the assumption of point contact between the tool and the workpiece often results in the consideration of only the forces in the three principal directions. This paper disregards these assumptions and confirms the existence of moments around the three principal directions through measurements of the mechanical factors during a turning operation. The experimental method used reveals, through energy assessment, the contribution of the various components of the forces and moments to the power consumed during classical and hard turning operations. By description of the various zones of contact chip/tool/ workpiece, a new modelling of 3D cutting is presented. The analytical model developed takes into account the complete geometry of the tool and introduces a new concept in modelling, especially of the secondary shear zone. A comparison between the power involved in the cutting process obtained with the model and with three other experimental devices confirms the relevance of 3D modelling, integrating the concept of moments at the tip of the tool. The energy balance equilibrium is then carried out correctly for the first time.