Springback In Sheet Metal Working

One of the most common metal working operations is bending.

Springback in sheet metal working.

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. Springback compensation a countermeasure of springback is carried out during the tool development phase. 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. Bending is one of the most frequent actions done to metal in press brake operation.

The spring back has to be compensated to achieve an accurate result. Details are given in the autoform glossary. After a bending operation residual stresses will cause the sheet metal to spring back slightly. The release of the elastic deformation is the spring back often observed at the end of a metal forming process.

The formation of sheet metal requires elastic plastic bending and stretching of the metal which contributes to springback. The final bend radius and bend angle can be approximated from the sheet thickness k factor material yield strength and modulus of elasticity and the initial bend angle and bend radius. Upon completion of sheet metal forming deep drawn and stretch drawn parts spring back and thereby affect the dimensional accuracy of a finished part. Springback and inside radius calculator for sheet metal.

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. These deformations may lead to a large amount of springback of the formed part. Springback is a semipredictable factor when working with sheet metal. 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.

Springback is inherent in sheet metal forming. The sheet metal forming process involves a combination of elastic plastic bending and stretch deformation of the workpiece. When the proportional limits of a specific material are reached or exceeded the material remains bent figure one. It can be can be understood by looking at a material s stress stain curve discussed in the module on tensile testing which characterizes the behavior of metal under applied force.

Spring back occurs when a metal is bent and then tries to return to its original shape. And if you re making profound radius bends in high strength steels hss it can be even more. This springback and inside radius calculator estimates the amount of angular change and the relaxing of bend radius that occurs when metal is bent and released from pressure. During forming the material is strained beyond the yield strength in order to induce permanent deformation.

It is desired to predict and reduce springback so that the final part dimensions can be controlled as much as possible. Springback is how the sheet metal tries to revert back into its straight form once it is bent.