Notice of RetractionThe study reduction of spring-back in U bending die process

Notice of Retraction

After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE´s Publication Principles.

We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.

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Bending process is an important process in the sheet metal forming in many industries. The main problem of the bending process is spring-back phenomenon after removing the punch. This research aims to reduce spring-back value of sheet metal in U bending process. The conventional U bending and corner setting technique were designed for experiments. The corner setting technique has reduced the thickness in bending area to 5, 10, 15 and 20 percent of the original sheet thickness. Clearance between punch and die of both processes was equal to same thickness. The spring-back value was investigated by commercial program code DEFORM 2D which able to analyze the stress and force in bending area. Electrolytic zinc coated carbon steel grade JIS; SECC, JIS; 440 and JIS; 590 having the thickness of 1 mm were employed as the workpiece material for all experiments. The result of three materials in conventional U bending die shows larger spring back than the corner setting technique. Moreover, the corner setting technique reduces spring back value in bending process but requires high bending force. Corner setting technique at 15% and 20% shows spring go of all parts. The FEM simulation results explain the spring-go phenomenon on the stress analysis. Comparisons between experimental and finite element method results were also performed.