FEM study of extrusion complexity and dead metal zone

Purpose: Quality of the extruded product and efficiency of the manufacturing process can be seriously affected by inconsistent metal flow through the extrusion die. Metal flow problems can also significantly reduce die life. Various researchers have investigated the effect of profile complexity on extrusion pressure, product quality, die life, etc. However, the relationship between shape complexity and metal flow through the extrusion die has not been studied in detail. Cold extrusion experiments on some solid profiles and simulations using the finite element method (FEM) have been used in this work to investigate the effect of profile complexity on dead metal zone and metal flow. Design/methodology/approach: Cold extrusion experiments were performed using flat-face dies of different complexities. 3D finite element simulation was carried out using the commercial finite element packages ANSYS and ANSYS-LSDYNA. Findings: Findings of this FEM study are that there appears to be no definite correlation between dead metal zone (DMZ) size and the currently existing definitions of extrusion shape complexity. Factors such as die profile symmetry and extrusion ratio may also play significant role in the formation of DMZ and distortion of metal flow through an extrusion die. Practical implications: The study can be of direct utility in extrusion die design improvement, and reduction of extrusion defects related to metal flow. Originality/value: The paper provides basis for a deeper understanding of the factors involved in the formation and development of dead metal zone (and related metal flow problems) in metal extrusion.