Analysis of friction and pressure distributions along the die during plane-strain drawing

Abstract

Using the model of the deforming asperities, analyzed by the upper-bound approach, an expression for the global friction factor m as a function of the power consumption J ∗ , of the processing parameters, and of pressure, is provided. Further, using the slug-equilibrium approach, as presented by Sachs, an expression for the required pressure and power of the deformation as a function of the global friction factor is found. Using an iterative procedure, the above two expressions have been solved for the interdependence between the pressure and global friction, during drawing in plane strain, thus satisfying both approaches. The global friction factor, as well as the pressure between the workpiece and the die, is plotted as a function of the location of the asperity along the die and of other independent parameters such as the die angle, the wedge angle, the local friction factor and the reduction of area during the process.