An analysis of external spline gear forming by an upper bound energy method

Closed-die forging of external spline gear forms is analysed using an upper bound elemental energy method. The kinematically admissible velocity held for the three-dimensional deformation was obtained on the assumption that the profiled surface of the tooth was straight but tapered. The upper bound to the deforming load necessary and the deformed configurations are predicted using integration of the formulation of energy expressions which were obtained from the presented velocity fields. Two different forging methods denoted here as A, viz. a side extrusion method and B, an upset forging method, the details of which are given in the text, were considered in the present analysis and the theoretical results compared with experimental ones. Experiments were carried out on plasticine as model material at room temperature where talcum powder was used as a lubricant. The present investigation revealed that the analytical method B predicts a reduced forging load and improved configuration better than method A for the forged products.