Processing animation simulation and FEM analysis of multi-stage cold forging of stainless automotive battery fastener

The study proposes processing animation simulation, FEM analysis, and experimental verification of multi-stage forging of stainless automotive battery fastener. The processing animation simulation can provide the realistic motions for each pass to realize how to work for the front punch and die. Stainless automotive battery fastener requires high dimension precision and narrow tolerance. In order to save the developing cost and accumulate more production design experiences, CAD/CAE technology has been used in multi-stage cold forging with five stages to shorten our developing cycle time. In this paper, the CAD drawing is made by Inventor 3D software, then import the STL file to DEFORM-3D software to do the settings of pre-process and simulation analysis. Effective stress, effective strain, velocity field, and forging force have been shown in this study. Finally, the actual manufacture measurement results compares with simulation datum to verify the analysis acceptance. After comparing the FEM simulation results with actual forming measurements, the error rate of washer diameter is increased in fourth stage. Although the measurement results are still in tolerance, the future work is to decrease the error rate through optimizing the mold design of fourth stage. The verification is performed to reduce the error rate according to the research method proposed in the study. On the other hand, the mold life in the actual forming is found to be easily damaged in the fifth stage. In the future, production improvement should be done through modifying the design of mold and die for the third and the fourth stages, the life of mold and die is explored to reduce the forging force in the fifth stage.