An Analysis on the Force Requirement of Combined Operations for Forward and Backward Tube Forming

Abstract

In the present study, the finite element analysis has been conducted to investigate the deformation characteristics of forward and backward can extrusion process using AA 1100 aluminum alloy tubes in terms of maximum forming load and extruded length ratio in a combined material flow. A commercially available code is used to conduct rigid-plastic FEM simulation. Hollow tubes are selected as initial billets and the punch geometries follow the recommendation of ICFG. Selected design parametrs involved in simulation includes punch nose radius, die corner radius, frictional condition, and punch face angle. The investigation is foucused on the analysis of deformation pattern and its characteristics in a forward tube extrusion combined simultaneously with backward tube extrusion process main in terms of force requirements for this operation according to various punch nose radii and backward tube thickness. The simulation results are summarized in terms of load-stroke relationships for different process parameters such as backward tube thickness, die corner radii, and punch face angle, respectively, and pressure distributions exerted on die, and comparison of die pressure and forming load between combined extrusion and two stage extrusion process in sequencial operation. Extensive analyses are also made to investigate the relationships between process parameters and extruded lengths in both forward and backward directions. It has been concluded from simulation results that a) the combined operation is superior to multi-stage extrusion process in sequential operation in terms of maximum forming load and maximum pressure exerted on die, b) the length of forward extruded tube increases and that of backward extruded tube decreases as the thickness ratio decreases, and c) the forming load is influenced much by the thickness ratio and the other design factors such as die corner radius and punch face angle does not affect much on the force requirement for the combined extrusion process.