Spring Back Effect In Sheet Metal Bending

Calculate and mitigating the springback effect in sheet metal.

Spring back effect in sheet metal bending.

The curved line in the air forming zone shows how springback changes at different bend angles. J material sci eng 6. Upon completion of sheet metal forming deep drawn and stretch drawn parts spring back and thereby affect the dimensional accuracy of a finished part. As shown in fig.

Spring back occurs when a metal is bent and then tries to return to its original shape. This phenomenon can easily be observed by bending a piece of wire or a short strip metal. The final bend radius and bend angle can be approximated from the sheet thickness k factor material yield. There are two basic views as to why spring back occurs one states that it is due to the displacement of molecules and the other considers spring back in terms of a stress strain diagram.

When the bending. Springback is the geometric change made to a part at the end of the forming process when the part has been released from the forces of the forming tool. Spring back occurs not sheets or plate but also in bending bars rod and wire of any cross section. Ao dametew aw gebresenbet t 2017 study the effects of spring back on sheet metal bending using mathematical methods.

In bottoming and coining bending methods that usually produce 90 degree bend angles the line curves to the right of the vertical axis showing how the metal springs forward to conform to the die angle. Due to this elastic recovery it is necessary to over bend the sheet a precise amount to acheive the desired bend radius and bend angle. Simple straight line bending will exhibit springback produce a simple 90 degree bend in any given sheet metal thickness of any grade and springback will occur. Akinlabi 7 stated about the bending operation and springback based geometrical inaccuracies of bent parts.

The release of the elastic deformation is the spring back often observed at the end of a metal forming process. The spring back has to be compensated to achieve an accurate result. When a metal forming tool is planned and designed to deform a work piece the shape imparted by the tool will be a combination of elastic and plastic deformation. This type of springback problem is easily adjusted for by adding simple over bend or compensation.

After a bending operation residual stresses will cause the sheet metal to spring back slightly. 1 the final bend angle after spring back is smaller and the final bend radius is larger than before. In this work sheet metal thickness and depth of forming effect on spring back is analyzed using finite element methods. Figure 3 coining bottom bending and air forming affect stressstrain properties differently.

The correcting bending force can elongate the inner and outer fiber in the deformation zone and achieve the forming effect.