DIE ENTRY PRESSURE DROPS IN PASTE EXTRUSION

Pressure drops for the extrusion of a perfectly plastic material throu gh smooth-walled dies with various reduction ratios and conical entry angles have been calculated by the large deformation elastic-plastic f inite element method. They are found to agree well with extrusion pres sures obtained from slipline field analyses for plane strain problems, and lie within the limits set by upper- and lower-bound solutions in axisymmetric cases. The results for axisymmetric dies are compared wit h the die entry pressure drop term in the Benbow-Bridgwater equation, used to describe the flow of pastes in a ram extruder. (C) 1998 Elsevi er Science Ltd. All rig hts reserved.