Influence of friction on die filling in counterblow hammer forging

The present work is the result of a reversed modeling, aimed at finding the best average friction factor on the tool/workpiece interface when simulating forging with the commercial FE code FORM2D. A vital restriction of FORM2D is its inability to distribute more than one friction factor for each tool. The studied process is the five-step counterblow hammer forging of pinions. Analyses are restricted to workpiece geometries, filling of the upper die and how the filling varies with friction. It is concluded that the most realistic filling of the upper die is obtained when maximum friction is applied to the lower die and a friction factor of roughly 0.2 to the upper die.