On the Effects of Eccentricity in Precision Forging Process

Initial location of the billet and the shape of die have an important effect on parameters of precision forging. Some of these effects are the contact stresses, material flow, distribution of stress, and also strain. In the present study, the die shape influences and the billet position in precision forging of two different shape groups have numerically and experimentally been investigated. Results proved that a properly positioned billet leads to smooth material flow without defects of producing burrs and underfilling during the forging process. Problems such as die underfilling and wear are primary factors to restrict the growth of the precision forging in many occasions. Results show that small eccentricities between die and billet cause noticeable effects on required forging forces. This relationship strongly depends on the die shape. In order to evaluate numerical results, a series of experiments were designed and implemented on axi-symmetric parts in three different billet positions. It is observed that the results of the finite element method (FEM) investigations and the experiments are in well agreement