Computer aided design and manufacture of streamlined extrusion dies

Abstract

Extrusion is one of the widely used metal forming processes. The extrusion process is carried out conventionally using a shear faced die, but shear faced dies have many practical problems such as a dead metal zone, more redundant work, breaking of whiskers and above all the design of a shear die is done based on experience. To eliminate the above problems, a new approach of designing the die known as a streamlined die is tried here. The streamlined extrusion die is designed based on the principle of constant area reduction over the length of the die. In this, a uniform flow of metal is ensured from the surface to the core and this can be a more scientific approach of die design. Many methods are available in the literature to design the streamlined extrusion die such as cubic polynomial curves, the area mapping technique, the line-mapping technique and the use of a genetic algorithm. For solving the problem of die design Stokes’ theorem is suggested, but a new approach of transforming the peripheral point on the surface of a cylinder to the corresponding point on the extruded square is obtained by an analytical method. An attempt is made to identify an analytical solution for designing a streamlined extrusion die for a square cross-section.