Sheet metal forming is a significan

Sheet metal forming is a significant manufacturing process for producing large variety of automotive parts and aerospace parts as well as consumer products. Deformation of sheet materials in the stamping process is classified by the four deformation modes, i.e. deep drawing, stretching, stretch flanging and bending[1]. Deep drawing is one of the widely used sheet metal working processes in the industries, to produce cup shaped components at a very high rate. Cup drawing, besides its importance as forming process, also serves as a basic test for the sheet metal formability. During the course of deep drawing, the following five processes take place[2]. They are: 1) pure radial drawing between the die and blank holder, 2) bending and sliding over the die profile, 3) stretching between the die and the punch, 4) bending and sliding over the punch profile radius, and 5) stretching and sliding over the punch face. Thus, the deep drawing process involves complex deformation mechanisms. The parameters that affect the success or failure of a deep drawing operation are the punch and die radii, the punch and die clearance, the press speed, thelubrication and the type and the extent of restraint to metal flow material in deep-drawn shapes. Among these, the die shoulder radius[3−6], punch nose radius[3−5] and the blank holder force[4−8] are considered to be the significant parameters in deep-drawing processes. Noticeable differences in forming behaviour on the stamping have been observed in the aluminum alloys. The relationship between the material, die design parameters and test parameters versus the deep drawability has not been well defined[9]. The quality characteristics chosen for the experiment should reflect as accurately as possible the design parameters under study. Thickness is one of the major quality characteristics in sheet metal formed part[4, 6]. The thickness is unevenly distributed in the part after deep drawing.