Abstract: Springback is a very important factor to influence forming accuracy of sheet metal. Accurate controlling of springback is the key to precision forming and tool design. In view of the shortcoming of traditional trial-and-error method used to correct springback, a technique based on dimensional analysis and orthogonal test is proposed to establish springback radius model for air-bending of sheet metal. And the scope of application of mathematical model for springback is discussed. With this model, the non-linear relation between springback radius of sheet metal and punch radius, sheet thickness, yield strength, Young’s modulus can be quantitatively solved, and it is used to design and make air-bending punch. Then, a semiellipse-shape workpiece, whose average errors are +0.63 /–0.65 mm, is made with the punch. The manufacturing results show that springback radius model, established with dimensional analysis and orthogonal test, is reasonable and effective. The modeling method is helpful to speeding up the progress of tool design and reducing production cost. It can be taken as a new approach for air-bending forming of sheet metal and tool design.

Key words: Dimensional analysis, Springback model, Sheet metal forming