A Feasibility Study on Performing Rotary Forging Process by Hexapod Table and Estimation of Forming Load for a Cylindrical Workpiece

Rotary forging is a forming method in which, the forces exerted on the workpiece can be reduced by using an inclined forming tool. The final shape of workpiece is formed gradually. The conventional machines used in this process, typically have separate rotational and linear (feeding) motions. The rotational motion is applied by an eccentric mechanism; the feeding motion is exerted with a linear actuator. These machines follow forward kinematics which does not consider the geometry of the workpiece to create motion profiles. Hence, having a special profile to be fully compatible with the piece is not possible. Such compatibility is beneficial to applying a more precise control on the material flow and achieving sound forgings. In this study, the feasibility of performing the rotary forging process on a hexapod table has been investigated. A hexapod machine available to the authors has been employed for this purpose. The hexapod table with six degrees of freedom is responsible for all shaping motions. This device can be used to produce different motion profiles for complex workpieces. The appropriate profiles are obtained through the inverse kinematics. The maximum force being applied on the hexapod actuators was calculated. Two circular and linear profiles were examined to practically shape cylindrical workpieces, and forming load was compared with conventional forging for producing lead cylindrical workpieces. Ultimately, the forming load ratios in rotary forging with liner profile to conventional forging and rotary forging with circular profile were obtained 0.27 and 0.49 respectively.