Effect of Blank Radius on Radial Stresses in Hydroforming Deep Drawing Process

This paper presents evaluation and effect of blank radius on radial stresses through mathematical formulations in hydroforming deep drawing process using castor oil medium. Hydraulic pressure can enhance the capabilities of the basic deep drawing process for making cups. In hydroforming deep drawing process, applying the hydraulic pressure on blank periphery in radial direction. It is obtained through the punch movement within the fluid chamber, which is provided in punch and die chambers. These two chambers are connected with the bypass path and it is provided in the die. During the process punch movement within the fluid chamber the pressure is generated in fluid and it is directed through the bypass path to blank periphery, the fluid film is created on the upper and lower surfaces of the blank and subsequently reduces frictional resistance and is to reduce tensile stresses acting on the wall of the semi drawn blank. The blank is taking at centre place in between blank holder and die surface with supporting of high pressurized viscous fluid. The radial stresses are produced in the blank in radial direction due to punch force applied on it, the shear stresses acted by viscous fluid on the both sides of blank, so apply viscosity phenomenon to this analysis. The radial stresses are determined in terms of viscosity of castor oil, blank geometry and process parameters for magnesium alloys.