Design of porthole aluminium extrusion dies through mathematical formulation

Abstract

A mathematical approach to solve the porthole die design problem is achieved by statistical analysis of a large amount of geometric data of successful porthole die designs. In cooperation with a leading extrusion company, a significant number of extrusion dies have been analysed. All of them were made of H-13 steel and the billet material was Al-6063 in all cases. Linear and logarithmic regression are used to analyse geometrical data of 596 different ports from 88 first trial dies. Non-significant variables or high correlated variables are discarded according to knowledge of the extrusion process and statistical criteria. Thus, this mathematical formulation is a way of summarizing in a single expression the experience accumulated in a large number of designs over time. Also, it could be used as a tool to help generate the starting point for designing high difficulty dies, in order to reduce the number of iterations of FEM simulation/modifications to achieve an optimal solution. It is not intended to eliminate the use of FEM simulation but to help speed up and improve the task of die design. This paper focuses on a validation model for a typical case of porthole dies for 6xxx series aluminium alloy: four cavities and four ports per cavity dies. But a broad way of research is open to generalise this model or extend it to other types of porthole dies.