A study on material flow in combined extrusion process

초록

This paper deals with an analysis of material flow in an extrusion process with a divide flow. The billet material flows easily into the corners of the die cavity and/or the material flow is controlled by the help of the ratio in reduction area, punch and mandrel corner radius, punch angle and friction factor over the billet-container interface. So the influences of this tool geometry and process condition on balanced material flow in a combined forward can and backward can extrusion process are explained. The FEM analysis has been used in order to investigate the effect of process parameters and also to estimate the stability of material flow. Deformation pattern and flow characteristics were examined in terms of design parameters such as volume ratio and friction condition, etc. Based on the simulation results, flow instability as a critical condition of extrusion process is defined and identified, where the flow direction is abruptly switched because of the slight value of some parameters. Therefore the numerical simulation works provide a combined extrusion process of stable cold forging process planning to avoid material flow instability.