INFLUENCE OF PUNCH ON BLANK HOLDER PRESSURE IN HYDROFORMING DEEP DRAWING PROCESS
Keywords:
Deep drawing, Hydro forming process, Fluid pressure, Blank holder pressure, Cfd model AnalysisAbstract
The hydro formed components are used in the aerospace, automotive, marine 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 within 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 pressure is obtained through ANSYS
Flotran CFD analysis software for castor oil. The evaluation of fluid 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. This pressure of fluid is used to evaluate the blank holding pressure. In this
process of hydro forming deep drawing the fluid pressure is equal to blank holder pressure is to be obtained. The
deformation of blank is uniform to get a required shape and also it prevents the blank failure during deformation due to
these two pressures are being equal. The pressure of fluid and blank holder pressure depends on punch speed. The fluid
pressure and blank holder pressure increases with increasing in the punch speed. The fluid pressure and blank holder
pressures are the dominant parameter for failure and success of forming of cups from the cylindrical blanks. In this
paper the numerical studies are carried on the determination of fluid pressure, blank holder pressure through punch by
varying its punch speed at constant its radius in hydro forming deep drawing process.
