Control Method of the Spring Back in Bending Micro and Precise Stamping Parts

The nature reason and the decisive factors of the spring back in bending process are studied in this paper. The analysis shows that opposite stress directions in the inner and outer fibers of the sheet material in the bending deformation region essentially contribute to the spring back, and controlling the bending moment created by this different stress directions is the essential method to control the spring back in bending process. The stress state in inner and outer fibers of the sheet material when the coining process is applied in the bending process is analyzed and compared with that when the coining process is not applied. Both the inner and outer fibers of the sheet material in bending process are subjected to the tensile stress after applying the coining process and the bending moment of the sheet is decreased greatly. By selecting reasonable coining depth and width, the coining process is applied to control the spring back in bending some micro and precision stamping part. The production result shows that the coining controlling method of the spring back has mighty high precision, simple mechanism structure, and is suitable very much for controlling the spring back in bending micro and precision stamping parts.