SUMMARY
In this study, the relative forging pressures of spur gears were evaluated. The precision forging of spur gears were analyzed by using upper bound method considering corner filling and bulging effect. Numerical and experimental studies were performed to investigate the effects of various parameters, such as number of teeth, modules, facewidth, bore diameter and friction factor on the relative forging pressure of spur gears. The results were compared with the previous studies and a simplified formula was suggested to predict the relative pressure of precision forging of spur gears. The predicted relative forging pressures obtained by the suggested formula are shown much closer to the experimental results for complete filling of the die cavity.