Influences of Material Thickness on Hole-flange Forming Limitation

In recent years, the hole-flanged components are not only fabricated for a thin sheet metal but they are also increasingly manufactured for a thick sheet metal especially in the automotive industry. However, most of the past researches have been studied the hole-flanging of thin sheet metal. In this study, the influences of material thickness were investigated using the finite element method (FEM) and laboratory experiments. Based on the stress distribution analysis, as the material thickness increased and the hole-flange forming ratio decreased, the effects of bending feature and the material stretching increased which resulted in the easy crack formation. The relationship between material thickness and hole-flange forming limitation was also investigated. In addition, the poor flatness on flange edge increased as the material thickness increased. The FEM simulation results showed the good agreement with the experimental results.