An Improved Hydroforming Process For ‘Unlimited’ Drawing Ratios

The goal of this work is to propose and test a new modified hydroforming process. External loads are applied to the workpiece on different surfaces by two independent fluid pressure sources: (a) the classical hydro‐forming fluid pressure, which ‘warps’ the cylindrical portion of the product with a prescribed pressure (about 200 bars in our case) and (b) the fluid rim pressure, which acts radially on the outer edge of the flange with a prescribed pressure (about 1000 bars in our case). A schematic view is shown in Fig. 1.The analysis shows that the modified hydro‐forming process preserves the usefulness of the product and postpones, or even eliminates, rupture at the bottom of the product by shifting the rupture to the product’s safer upper‐portion. The rim pressure acts on the rim of the flange and ‘extrudes’ the material inward, resulting in significant reduction of tensile stress in the blank, which otherwise promotes undesired early rupture.One major complication in the design of the present experiment...