Modeling approach to estimate the elastic characteristics of workpiece and shrink-fitted die for cold forging

The dimension of cold-forged part is different from that of the forging tool. The difference is influenced with various features. In this study, FEM analyses are performed to investigate the elastic characteristics of die and workpiece. For a comparison with the measured die deflections and dimension of forged part, five FEM modeling approaches have been proposed and simulated by using a commercial FEM-code, DEFORM-2DTM. Among the various modeling approaches, when the die and workpiece are considered as an elastic material and an elasto-plastic material, respectively, during the forming simulation, the FEM analysis results are well agreed with the experimental results. Furthermore, when dimensional change and stress distribution of shrink-fitted die is considered with realistic die manufacturing, the estimated dimension of forged part are well fitted to the experimental results within the range of ±10 μm. Finally, the reasonable modeling approaches have been proposed that the shrink fitting and machined die dimension could be practically considered and lead to a successful prediction of dimension for cold-forged part.