numerical study and genetic algorithm optimization of hot extrusion process to produce rectangular waveguides

rectangular waveguide (wr) is one of the earliest types of transmission lines. rectangular waveguide can be produced by hot extrusion process. in this paper, the hot extrusion process of cuzn5 rectangular waveguide was investigated by finite element method (fem). in addition, genetic algorithm method (ga) was used to optimize the die geometry and process conditions to achieve the lowest magnitude of extrusion force. die geometry was introduced in terms of die length and billet hole diameter under various frictional conditions. it was found that die length and billet hole diameter had contradictory effects on the extrusion force. the optimum die length of l=40cm was obtained for µ=0.025 and that of l=20cm was achieved for µ=0.05, 0.075 and 0.1. moreover, the optimum billet hole diameter of d=3cm was obtained for all frictional conditions. the experimental procedure was carried out to verify the accuracy of results. the extrusion force of 1600 t was obtained from experiment for the friction coefficient of µ≈0.1. the estimated force of such a condition with ga is 1577 t which has a good agreement with experimental result.