Force model for complex profile tool in broaching Inconel 718

Complex profile broaches are widely used in the manufacture of complex parts of aero-engines, but the forces in the broaching process are difficult to predict and control. A new numerical model for broaching force with complex profile tools was presented, which considered the area and arc length of the curved shear zone boundary. The area and arc length were calculated by the curve function of the boundary, which is firstly predicted by FEM simulation. Then, an experimental device was set up to carry out the broaching experiment with straight profile tools and complex profile tools in accordance with the progressive depth of the cut. Based on the experiments, the traditional broaching model and the modified model with the complex profile tool have been established. Compared with the traditional force model, the accuracy of the modified model has been moderately improved. Furthermore, the modified main broaching force (Y direction) model and the normal force (Z direction) model show a significant improvement in accuracy of 4.8% and 9.7%, respectively, which suggests that the projection area of curved shear zone A₁ and the projection arc length of curved shear zone l₁ have a big impact on the broaching process. It is firmly believed that the modified model proposed in this paper can provide guidance for the design of complex profile tools and facilitate the efficient and high-precision machining of complex parts.