An Experimental Study of Springback of Bent Sheet Metal Parts

Bending is the uniform straining of material around a straight axis and is used commonly in various sheet metal industrial products. Since all materials have a finite modulus of elasticity, plastic deformation is followed by some elastic recovery when the load is removed. In bending processes this phenomenon is called springback. Springback occurs not only in flat sheets or plate, but also in bars, rods, etc., and is one of the key factors to influence the quality of bent sheet metal parts. The amount of springback should be known in order to produce bent sheet metal parts within acceptable tolerance limits. There are many parameters which have influence on springback, one of them is strain hardening. The aim of the experimental work, described in the paper, was to determine the influence of the effective strain to springback ratio and springback angle of sheet metal specimens. Many experiments have been done to find out the amount of springback for different values of effective strain and different thickness of metal sheets. Different specimens were used for the experimental determination of springback ratio and springback angle and were bent in a special bending tool. Statistical analysis methods were used for determination of mathematical models. This study is considered to be helpful to understand springback phenomena in metal forming processes.