Influence of variables in deep drawing of AA 6061 sheet

Deep drawing is one of the most important processes for forming sheet metal parts. It is widely used for mass production of cup shapes in automobile, aerospace and packaging industries. Cup drawing, besides its importance as forming process, also serves as a basic test for the sheet metal formability. The effect of equipment and tooling parameters results in complex deformation mechanism. Existence of thickness variation in the formed part may cause stress concentration and may lead to acceleration of damage. Using TAGUCHI's signal-to-noise ratio, it is determined that the die shoulder radius has major influence followed by blank holder force and punch nose radius on the thickness distribution of the deep drawn cup of AA 6061 sheet. The optimum levels of the above three factors, for the most even wall thickness distribution, are found to be punch nose radius of 3 mm, die shoulder radius of 8 mm and blank holder force of 4 kN.