Analysis on effect of die fillet radius and draw bead on hemispherical cup forming

The die is specialized tool used in manufacturing industries like automobile, appliance, aerospace etc. to form a wide variety of parts and component through sheet metal forming process. The quality of sheet metal part is secured by the material flow into the die cavity. The considered parameter in this paper is the die fillet radius, which greatly affect the metal flow during sheet metal forming process. In sheet metal forming process die fillet radius is an important and effective parameter for increasing forming limit of metal sheets as well as effectively treating some other common forming problem like distortion and wrinkling. In this present work examine the effect of die fillet radius on hemispherical cup forming, which is analyzed by using FE based HYPERFORM software. The obtained results are compared with literature results. Furthermore same simulation analysis have been carried out using circular draw bead with various values of die fillet radius ranged between 1.5mm to 4.5mm. In simulation, Strain and thickness variations were measured for the cup drawing. Forming Limit Diagrams are used to determine the safe limit of the sheet metal operation. The results demonstrate excellent agreements between the numerical method and experiment.