Determination of Blank Holder Pressure in Hydroforming Deep Drawing Process

R Uday Kumar1 , P Ravinder Reddy2, and A V Sita Ramaraju3
1.Department of Mechanical Engineering, Mahatma Gandhi Institute of Technology, Gandipet, Hyderabad 500075, Andhra Pradesh, India.
2.Department of Mechanical Engineering, Chaitanya Bharathi Institute of Technology, Gandipet, Hyderabad 500075, Andhra Pradesh, India.
3.Department of Mechanical Engineering, JNTUH College of Engineering, Kukatpalli, Hyderabad 500085, Andhra Pradesh, India.
Abstract— The hydro forming deep drawing process is a sheet metal forming process. In this process the pressurized fluid is used as a medium. This pressurized fluid is used to form different component shapes. The process allows manufacturing lighter complex shapes more with increased strength at lower cost compared to more traditional techniques such as stamping, forging, casting or welding. The hydro formed components are used in the aerospace, automotive and other industries. In hydro forming deep drawing process, applying the hydraulic pressure in radial direction on the periphery of the blank is obtained through the punch movement with in the fluid chamber. The fluid is taking place in the die cavity and punch chamber and these are connected with the bypass path provided in the die. The gap is provided between die surface and blank holder bottom surface for movement of pressurized fluid and blank in the process. The pressure is generated in fluid due to punch movement with in the fluid chamber and directed through the bypass path to the blank periphery and is to reduce tensile stresses acting on the wall of the semi drawn blank. The fluid pressures obtained from ANSYS Flotran CFD analysis software for using the fluids such as olive oil, heavy machine oil and castor oils. The Evaluation of fluids pressure with changing the punch speed at constant punch radius. The pressure of fluid is acting radially on surface of blank during the process. The radial pressure of fluid is controlled by the blank holder pressure. As these two pressures are equal, the deformation of blank is uniform to get a required shape and also it prevents the blank failure during deformation. The pressure of fluid depends on punch speed. The fluid pressure increases with increase in the punch speed. The fluid pressure is the dominant parameter for failure and success of forming of cups from the cylindrical blanks. This pressure of fluid is used to evaluate the blank holding pressure. In this hydro forming deep drawing process the fluid pressure is equal to blank holder pressure is obtained. In this paper the studies are carried on the determination of fluid pressure, blank holder pressure through punch speed in hydro forming deep drawing process. In this process, the pressurized fluid is utilized for many purposes as the sheet metal blank is supported in entire forming process, elimination of fracture in deformation of cup and formation of wrinkles on the wall and edges of the cup are minimized.

Index Terms— Hydro forming process, Deep drawing, Fluid pressure, Fluid model, CFD analysis, Geometric modeling

Cite: R Uday Kumar, P Ravinder Reddy, and A V Sita Ramaraju, " Determination of Blank Holder Pressure in Hydroforming Deep Drawing Process," International Journal of Mechanical Engineering and Robotics Research, Vol. 1, No. 2, pp. 242-249, July 2012.

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