Experimental and Numerical Investigation of Hole-Flanging Process with Rubber Punch

Hole-flanging process is widely being used in metal forming industry. Using elastomeric punch instead of the rigid one may enhance the quality of surface finish of the produced part. The objective of this paper is to investigate the sheet metal hole-flanging process with soft punch. This investigation is carried out via numerical and experimental analysis using polyurethane rubber with hemispherical end as flexible tool. Material of workpiece is the aluminum AA 1050-H14. Numerical simulation of the flexible hole-flanging process is performed with Abaqus/ Explicit. A Mooney-Rivlin model is adopted to predict the hyperelastic parameters of rubber punch with Shore hardness 70 A. The Coulomb friction law is adopted to model the contact between soft punch/part and part/rigid die. An experimental set up is developed to produce flanges. Numerical result presents a comparison between classical hole-flanging process with rigid tool and flexible process with rubber tool in term of variation of thickness distribution along the flange wall. Using soft tool with hemispherical end may improve the formability of aluminum flanged part compared to conventional forming technique. Numerical prediction of thickness distribution is assessed with the experimental measurement along the wall of the flanged part for validation purpose.