Prediction of surface topography in lubricated sheet metal forming

This study develops new model that is suitable for predicting the surface topography of the products of lubricated sheet metal forming. In the lubrication analysis, a finite element model is derived for the average Reynolds equation, no matter whether the tooling surface comes into contact with workpeice surface or not. With regard to the asperity contact theory and surface parameter analysis, a novel model takes account of the smoothing, roughening and tool elastic microwedge effects on the surface of the workpiece. A model was combined with a finite element membrane code of axisymmetric stretch forming to predict the contact area ratio and the surface roughness. Numerical results revealed that the new model is consistent with the experimental results. The superiority of the new model over the conventional model is that it predicts the surface roughness more accurately during the lubricated sheet metal forming process.