Assessment of the Optimization Strategy for Nitrogen Cooling Channel Design in Extrusion Dies

Aluminum extrusion is an efficient industrial process. However, one of the main problems is related to the temperatures developed during the process that can detrimentally affect the achievable productivity, profile quality and/or die life. Cooling of the die with liquid nitrogen represents an efficient solution to overcome this limit but a further issue arises lying in the number of process and design variables that need to be managed in order to set-up of an efficient system. In this context, a 3D FE model of the extrusion process, coupled with a 1D model of the cooling channel, previously proposed by the authors, has been integrated in an optimization platform in order to iteratively and automatically adjusts the channel geometry and the process variables gaining to a final optimal solution in terms of thermal balance, cooling efficiency and nitrogen consumption. The original channel design used during the extrusion of industrial hollow AA6060 profile guaranteed an efficient but unbalanced cooling with a maximum temperature deviation of 60 °C registered by the thermocouple positioned around the bearings. The optimized designs showed temperature deviations below the 16 °C as well as the reduction of 50% in terms of nitrogen consuming.