Optimization of working conditions and increase of productivity of aluminum hot extrusion press based on finite element analysis

Abstract

Abstract. The finite element simulation of extrusion allows a precise analysis of the metal flow, but also a detailed evaluation of the various parameters involved in the process: temperatures, pressures, velocities and stresses. The press productivity is directly related to the extrusion velocity. In turn, the maximum achievable extrusion velocity is limited by the exit temperature of the formed profile. Traditionally, most presses set a general billet temperature conservatively to ensure that extrusion does not exceed the pressure and stress limits for most dies. This study aims to provide an additional and non-exclusive methodology to increase productivity based on the correct choice of the billet temperature at the press with the help of a previous analysis by means of finite element simulation. A controlled reduction of the billet temperature makes it possible to increase the extrusion velocity while keeping the outlet temperature, stresses and pressure within the admissible range. The use of finite element simulation avoids iterative processes with several press trials and avoids the risks of excessive press pressure or tool stresses. Thus, it allows a quick determination of the optimum temperature and performs risk-free prediction. To demonstrate the use of the methodology, a billet temperature optimisation for an example die has been developed using the simulation software Qform UK. Together with the theoretical analysis, the results of the real die in the press in collaboration with Alumex PLC (Sri Lanka) are shown. This methodology is shown to be effective and may be of particular interest to companies already using extrusion simulation for other uses, such as die design.